DRAFT 

FLORIDA DEPARTMENT OF ENVIRONMENTAL PROTECTION 

Division of Water Resource Management, Bureau of Watershed Management

SOUTHWEST DISTRICT • LAKE HANCOCK BASIN • PEACE RIVER PLANNING UNIT 

TMDL Report 

Dissolved Oxygen 

and Nutrient TMDLs for 

Lake Hancock and 

Lower Saddle Creek 

(WBID 1623L & 1623K) 

Zack Shelley 

Douglas Gilbert 

Kevin Petrus 

November 2005 

DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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Acknowledgments 

This study could not have been accomplished without significant contributions from staff in the 

Florida Department of Environmental Protection’s (the Department) Watershed Assessment 

Section. The Department also recognizes the substantial support and assistance from the 

Department’s Tampa District Office, the Southwest Florida Water Management District (SWFWMD), 

the Polk County Natural Resource Division, Soil and Water Engineering Technology, Inc. (SWET), 

and Quantitative Environmental Analysis (QEA), LLC, and their contributions towards 

understanding the issues, history, and processes at work in the Lake Hancock and Lower Saddle 

Creek watersheds. 

Editorial assistance provided by Daryll Joyner and Jan Mandrup-Poulsen. 

 

For additional information on the watershed management approach and impaired waters in 

The Peace River, Myakka River, and Sarasota Bay Planning Units, contact: 

Tom Singleton 

Florida Department of Environmental Protection 

Bureau of Watershed Management 

Watershed Planning and Coordination Section 

2600 Blair Stone Road, Mail Station 3565 

Tallahassee, FL 32399-2400 

tom.singleton@dep.state.fl.us 

Phone: (850) 245-8561; Suncom: 205-8561 

Fax: (850) 245-8434 

Access to all data used in the development of this report can be obtained by contacting: 

Kevin Petrus, Environmental Manager 

Florida Department of Environmental Protection 

Bureau of Watershed Management 

Watershed Assessment Section 

2600 Blair Stone Road, Mail Station 3555 

Tallahassee, FL 32399-2400 

Kevin.petrus@dep.state.fl.us 

Phone: (850) 245-8459; Suncom: 205-8459 

Fax: (850) 245-8536 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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Contents 

CHAPTER 1: INTRODUCTION................................................................................................. 1 

1.1 Purpose of Report ............................................................................................................1 

1.2 Identification of Waterbody .............................................................................................1 

1.3 Lake Hancock Historic Water Quality.............................................................................7 

1.4 Lake Hancock Background Information.........................................................................9 

1.5 TMDL Background Information.....................................................................................10 

CHAPTER 2: STATEMENT OF WATER QUALITY PROBLEM ......................................... 12 

2.1 Legislative and Rulemaking History.............................................................................12 

2.2 Information on Verified Impairment..............................................................................12 

CHAPTER 3. DESCRIPTION OF APPLICABLE WATER QUALITY STANDARDS AND 

TARGETS..................................................................................................................................... 25 

3.1 Classification of the Waterbody and Criteria Applicable to the TMDL ......................25 

3.2 Dissolved Oxygen Criterion for Lakes and Streams...................................................25 

3.3 Interpretation of the Narrative Nutrient Criteria for Lakes and Streams.................26 

3.3.1 Criteria Definitions........................................................................................................28 

3.4 Paleolimnological Information for the Lake Hancock Basin ......................................29 

Lake Hancock.........................................................................................................................29 

Lake Hollingsworth................................................................................................................30 

Lake Parker ............................................................................................................................30 

CHAPTER 4: ASSESSMENT OF SOURCES.......................................................................... 32 

4.1 Overview of Modeling Process......................................................................................32 

4.2 Potential Sources of Nutrients in the Lake Hancock and Lower Saddle Creek 

Watersheds ............................................................................................................................34 

4.2.1 Point Sources...............................................................................................................34 

Lake Lena Sub-basin.............................................................................................................34 

Lake Parker Sub-basin..........................................................................................................35 

Municipal Separate Storm Sewer System Permittees........................................................37 

4.2.2 Nonpoint Sources and Land Uses ..............................................................................39 

Polk County Population ........................................................................................................43 

Polk County Septic Systems ................................................................................................43 

4.3 Estimating Point and Nonpoint Source Loadings...............................................43 
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Model Approach ....................................................................................................................43 

Land Use and Soils ...............................................................................................................46 

Hydrologic Data .....................................................................................................................46 

Depressions...........................................................................................................................47 

Rainfall....................................................................................................................................49 

Control Structures.................................................................................................................49 

Ground Water.........................................................................................................................49 

WAM Model Linkage to the BATHTUB Model .....................................................................51 

WAM and BATHTUB Calibration ..........................................................................................51 

Lake Hancock Basin Existing Land Use Loadings ............................................................52 

CHAPTER 5: DETERMINATION OF ASSIMILATIVE CAPACITY ................................... 56 

5.1 Determination of Loading Capacity ..............................................................................56 

5.1.1 Rainfall..........................................................................................................................56 

5.1.2 Model Calibration ........................................................................................................57 

Watershed Assessment Model (WAM) ................................................................................57 

BATHTUB Model....................................................................................................................57 

5.1.3 Background Conditions..............................................................................................60 

WAM Model ............................................................................................................................60 

BATHTUB Model....................................................................................................................61 

5.2 Selection of the TMDL Target........................................................................................61 

5.3 Critical Conditions..........................................................................................................67 

5.4 Wasteload Allocation .....................................................................................................67 

CHAPTER 6: DETERMINATION OF THE TMDL................................................................ 74 

6.1 Expression and Allocation of the TMDL.......................................................................74 

6.2 Load Allocation (LA) ......................................................................................................75 

6.3 Wasteload Allocation (WLA)..........................................................................................75 

NPDES Wastewater Discharges...........................................................................................75 

NPDES Stormwater Discharges ...........................................................................................75 

6.4 Margin of Safety (MOS) ..................................................................................................75

6.5 Lower Saddle Creek .......................................................................................................76 

CHAPTER 7: NEXT STEPS: IMPLEMENTATION PLAN DEVELOPMENT AND 

BEYOND ...................................................................................................................................... 77 

REFERENCES ............................................................................................................................ 78 

 APPENDICES ............................................................................................................................ 83 
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Appendix A: Background Information on Federal and State Stormwater Programs.....83 

Appendix B: Lake Hancock and Lower Saddle Creek Total Nitrogen, Total Phosphorus, 

Chlorophyll a, and Dissolved Oxygen Monitoring Data.....................................................84 

Appendix C: Lake Hancock Basin Modeled Lakes TSI for PC, Background, TMDL 

Target, and TSI-Unit Percent Reduction..............................................Separate Attachment

Appendix D: Lake Hancock Basin Modeled Lakes Mass for TN and TP for Calibrated 

Model, TMDL, and Percent Reduction .................................................Separate Attachment

Appendix E: Lake Hancock Basin Modeled Lakes Annual Average Concentrations for 

TN, TP, and Chlorophyll a..........................................................Separate Attachment

Appendix F: SWET Watershed Assessment Model (WAM) of the Lake Hancock Basin 

Final Report..........................................................................................................................105 

Appendix G: QEA BATHTUB Model Framework for the Lake Hancock Basin 

Final Report.................................................................................................. ....105 

Appendix H: WAM Watershed Assessment Model, Model Documentation and Users 

Manual, Soil and Water Engineering Technology, Inc., May, 2005............................105 

Tables 

Table 1.1 Summary Statistics of Historical Water Quality in Lake Hancock form 1985 to 1999.....................7 

Table 1.2 Summary Statistics of Historical Water Quality in Lake Hancock from March 2004 to 

February 2005............................................................................................................................8 

Table 2.1 Water Quality Summary Statistics for TN, TP, and Chlorophyll a for Lake Hancock and Lower 

Saddle Creek from 1992 to 2004......................................................................................................12 

Table 3.1 Screening Level Values Based on STORET Data from 1979 to 1987.........................................23 

Table 4.1 Lake Hancock Basin Existing Land Use Descriptions. ..........................................................34 

Table 4.2 Lake Gibson and Lake Crago Existing Land Use Water Volume and Loadings for TN and TP 

From 1994 to 2003.....................................................................................................................53 

Table 4.3 Lake Bonny and Lake Parker Existing Land Use Water Volume and Loadings for TN and TP 

From 1994 to 2003.....................................................................................................................53 

Table 4.4 Lake Lena and Lake Banana Existing Land Use Water Volume and Loadings for TN and TP 

From 1994 to 2003.....................................................................................................................54 

Table 4.5 Lake Hancock and Lake Hollingsworth Existing Land Use Water Volume and Loadings for TN and 

TP from 1994 to 2003.................................................................................................................54 

Table 4.6 Lake Bentley and Lake Spirit Existing Land Use Water Volume and Loadings for TN and TP 

from 1994 to 2003......................................................................................................................55 

Table 4.7 Lake Eagle Existing Land Use Water Volume and Loadings for TN and TP from 1994 to 

2003.......................................................................................................................................55 

Table 5.1 Bartow and Lakeland, Florida, Rainfall Stations used for Model Loading and Calibration............57 

Table 5.2 Lake Hancock TSI for PC, Background, TMDL Target, and TSI-Unit Reduction........................63 

Table 5.3 Lake Hancock Mass for TN and TP for Calibrated Model, TMDL, and Percent Reductions..........63 

Table 5.4 Lake Hancock Annual Average Concentrations for TN, TP, and Chlorophyll a...........................64 

Table 5.5 Flow in Cubic Hectometers Per Year for Each Source...............................................................68 

Table 5.6 Difference Between PSPC and PSMAX and PSPC and NoPS Flow (hm3/yr).............................69 

Table 5.7 Total Phosphorus Mass (kg/yr)...................................................................................................70 

Table 5.8 Total Phosphorus Mass Difference Between PSPC and PSMAX and PSPC and NoPS..............71 

Table 5.9 Total Nitrogen Mass (kg/yr).........................................................................................................72 

Table 5.10 Total Nitrogen Mass Difference Between PSPC and PSMAX and PSPC and NoPS.................73 

Table 6.1 Lake Hancock and Lower Saddle Creek TMDL Load Allocations............................................74 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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Figures 

Figure 1.1 Southwest Florida Group 3 WBIDs and Major Metropolitan Areas Surrounding the Lake 

Hancock Watershed and Lower Saddle Creek Sub-basin...............................................................3 

Figure 1.2 Lake Hancock WBID 1549B and Monitoring Stations.......................................................5 

Figure 1.3 Lower Saddle Creek Canal WBID 1549A and Monitoring Stations......................................6 

Figure 2.1 TSI Results for Lake Hancock Calculated from Annual Average Concentrations of TN, TP, and 

Chlorophyll a from 1984 to 2004..........................................................................................................15 

Figure 2.2 Total Nitrogen Monthly Results for Lake Hancock from 1992 to 2004.................................15 

Figure 2.3 Total Nitrogen Annual Mean Results for Lake Hancock from 1992 to 2004..........................16 

Figure 2.4 Total Phosphorus Monthly Results for Lake Hancock from 1992 to 2004...............................16 

Figure 2.5 Total Phosphorus Annual Mean Results for Lake Hancock from 1992 to 2004......................17 

Figure 2.6 Chlorophyll a Monthly Results for Lake Hancock from 1992 to 2004.....................................17 

Figure 2.7 Chlorophyll a Annual Mean Results for Lake Hancock from 1992 to 2004............................18 

Figure 2.8 Dissolved Oxygen Monthly Results for Lake Hancock from 1992 to 2004...............................18 

Figure 2.9 Dissolved Oxygen Annual Mean Results for Lake Hancock from 1992 to 2004.....................19 

Figure 2.10 Total Nitrogen Monthly Results for Saddle Creek Below Lake Hancock from 1992 to 

2004...........................................................................................................................................................19 

Figure 2.11 Total Nitrogen Annual Mean Results for Saddle Creek Below Lake Hancock from 1992 

to 2004...............................................................................................................................20 

Figure 2.12 Total Phosphorus Monthly Results for Saddle Creek Below Lake Hancock from 1992 to 

2004...........................................................................................................................................................20 

Figure 2.13 Total Phosphorus Annual Mean Results for Saddle Creek Below Lake Hancock from 1992 

To 2004.............................................................................................................................21 

Figure 2.14 Chlorophyll a Monthly Results for Saddle Creek Below Lake Hancock from 1992 to 

2004..........................................................................................................................................................21 

Figure 2.15 Chlorophyll a Annual Mean Results for Lower Saddle Creek from 1992 to 

2004.........................................................................................................................................................22 

Figure 2.16 Dissolved Oxygen Monthly Results for Saddle Creek Below Lake Hancock from 1992 

to 2004...............................................................................................................................22 

Figure 2.17 Dissolved Oxygen Annual Mean Results for Saddle Creek Below Lake Hancock from 1992 

to 2004...............................................................................................................................23 

Figure 4.1 Aerial View of the Lake Hancock and Saddle Creek Watershed, Polk, County, 

Florida................................................................................................................................33 

Figure 4.2 Lake Hancock and Lower Saddle Creek Watershed Lake Control Structures and Active 

NPDES Facilities...................................................................................................................36 

Figure 4.3 Phase I MS4 Coverage Area for the Lake Hancock Basin...............................................38 

Figure 4.4 Lake Hancock and Saddle Creek Existing Land Use Coverage..........................................41 

Figure 4.5 Lake Hancock Basin Natural Background Land Use Coverage.........................................42 

Figure 4.6 WAM Conceptual Routing Diagram..............................................................................44 

Figure 4.7 WAM Dynamic Modeling Approach..............................................................................45 

Figure 4.8 Model Schematic Depicting the Interconnected Eleven Lakes Modeled for the Lake Hancock 

Watershed..........................................................................................................................46 

Figure 4.9 Model Reaches and Estimated Depressions Attenuation Distances...................................47 

Figure 4.10 Rainfall Stations and Zones......................................................................................49 

Figure 4.11 Surface Water and Ground Water Distribution Zones.....................................................50 

Figure 5.1 Lake Hancock Total Nitrogen Measured, Un-Calibrated and Calibrated Data from 

1994 to 2003..............................................................................................................................................58 

Figure 5.2 Lake Hancock Total Phosphorus Measured, Un-Calibrated and Calibrated Data from 

1994 to 2003.......................................................................................................................59 

Figure 5.3 Lake Hancock Chlorophyll a Measured, Un-Calibrated and Calibrated Data from 

1994 to 2003.......................................................................................................................59 

Figure 5.4 Lake Hancock TSI Measured, Un-Calibrated and Calibrated Data from 1994 to 2003...........60 

Figure 5.5 Lake Hancock Total Nitrogen Target TMDL, Background Calibration, and L50-IL75 

from 1994 to 2003................................................................................................................65 
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Figure 5.6 Lake Hancock Total Phosphorus Target TMDL, Background Calibration, and L50-IL75 

from 1994 to 2003...............................................................................................................65 

Figure 5.7 Lake Hancock Chlorophyll a Target TMDL, Background Calibration, and L50-IL75 

from 1994 to 2003................................................................................................................66 

Figure 5.8 Hancock TSI Target TMDL, Background Calibration, and L50-IL75 from 

1994 to 2003.........................................................................................................................66 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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Web sites

FLORIDA DEPARTMENT OF ENVIRONMENTAL PROTECTION, BUREAU OF 

WATERSHED MANAGEMENT 

TMDL Program 

http://www.dep.state.fl.us/water/tmdl/index.htm

Identification of Impaired Surface Waters Rule 

http://www.dep.state.fl.us/water/tmdl/docs/AmendedIWR.pdf

STORET Program 

http://www.dep.state.fl.us/water/storet/index.htm

2000 305(b) Report 

http://www.dep.state.fl.us/water/305b/index.htm

Criteria for Surface Water Quality Classifications 

http://www/dep.state.fl.us/legal/legaldocuments/rules/ruleslistnum.htm

Basin Status Report for the Lake Hunter Basin 

http://www.dep.state.fl.us/water/tmdl/stat_rep.htm

Assessment Report for the Lake Hunter Basin 

http://www.dep.state.fl.us/water/tmdl/stat_rep.htm

Allocation Technical Advisory Committee (ATAC) Report 

http://www.dep.state.fl.us/water/tmdl/docs/Allocation.pdf

U.S. ENVIRONMENTAL PROTECTION AGENCY, NATIONAL STORET PROGRAM 

http://www.epa.gov/storet/

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Chapter 1: INTRODUCTION 

1.1 Purpose of Report 

This report presents the Total Maximum Daily Load (TMDL) for nutrients and dissolved 

oxygen (DO) for Lake Hancock and Saddle Creek Below Lake Hancock, which are located in 

the Lake Hancock Basin. For this TMDL report, the Saddle Creek Below Lake Hancock 

waterbody will be referred to as “Lower Saddle Creek.” Lake Hancock and Lower Saddle 

Creek are essentially the headwaters of the Peace River and have a direct impact on water 

quantity and quality of the downstream river reaches. The lake and creek were verified as 

impaired for nutrients and low DO using the methodology in the Identification of Impaired 

Surface Waters Rule [IWR, Rule 62-303, Florida Administrative Code (F.A.C.)]. The lake and 

creek were included on the Verified List of impaired waters that was adopted by Secretarial 

Order on June 17, 2005. The TMDLs establish the allowable loadings to the lake and creek 

that would restore the waterbodies so that they meet their applicable water quality criteria for 

nutrients and DO. 

1.2 Identification of Waterbody 

Lake Hancock is located southeast of the City of Lakeland, north of Bartow and west of Winter 

Haven in Polk County, Florida. The estimated surface area of the lake is 4,533 acres, and the 

approximate total volume of the lake is 19,795,031.5 m3

 (16,048 acre-feet), with an average 

depth of 5 ft (1.5 m). The surface water drainage area of the lake is approximately 140 square 

miles. The surface water drainage area of Lake Hancock and Lower Saddle Creek is 

approximately 157 square miles. The Lake Hancock and Lower Saddle Creek watersheds 

are illustrated in Figure 1.1, which also shows the eight major sub-basins that make up the 

Lake Hancock watershed. The watershed’s land use designations are primarily urban, citrus, 

and abandoned phosphate mine lands. The normal pool topographic elevation of the water 

surface is approximately 97.7 feet National Geodetic Vertical Datum (NGVD) (BCI Engineers 

and Scientists, Inc., 2005). Primary tributaries flowing into Lake Hancock include Banana 

Lake Canal, Lake Lena Run, and Saddle Creek Above Lake Hancock (here after referred to 

as Middle and Upper Saddle Creek). 

Significant sub-basins draining into Lake Hancock and Lower Saddle Creek include Middle 

and Upper Saddle Creek, the Lake Parker sub-basin (which includes Lakes Bonny, Gibson, 

Crago, and Parker); the Banana Lake sub-basin (which includes Lakes Bentley, 

Hollingsworth, Banana, and Banana Lake Canal); the Lake Lena sub-basin (which includes 

Lakes Areitta, Ariana, Lena, and Lake Lena Run); and the Eagle Lake sub-basin (which 

includes Lakes Thomas, Sears, Spirit, Eagle, and Millsite). 

Lower Saddle Creek is the outlet channel for Lake Hancock. The creek’s confluence with the 

Peace Creek Drainage Canal forms the headwaters of the Peace River, which travels 

approximately 105 miles to Charlotte Harbor. In 1963, the Outfall Control Structure P-11 was 

constructed approximately 3,500 feet south of Lake Hancock in Lower Saddle Creek to 

regulate discharge from the lake and reduce flooding in downstream reaches during high 

rainfall/water events (Environmental Research and Design, Inc., 1999). Structure P-11 was 

constructed to replace a structure that consisted of concrete, timber piles, and removable 

boards. This current structure is operated and maintained by the Southwest Florida Water 

Management District (District). Two 7-foot high by 20-foot wide radial gates with an invert of 

91.7 feet NGVD are used to regulate the flows out of the lake. Since construction of the P-11 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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structure, the water level in the lake has averaged between elevations of 97 and 98.5 feet 

NGVD (BCI Engineers and Scientists, Inc., 2005). 
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Figure 1.1 Southwest Florida Group 3 WBIDs and Major Metropolitan Areas 

 Surrounding the Lake Hancock Watershed and its Major Sub-basins
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For assessment purposes, the Department has divided the Lake Hancock Basin into water 

assessment polygons with a unique waterbody identification (WBID) number for each 

watershed or stream reach. The lake has been given the WBID number of 1623L, and Lower 

Saddle Creek has been given the WBID number 1623K. The Lake Hancock WBID and its 

sampling/monitoring stations are shown in Figure 1.2. The Lower Saddle Creek WBID and its 

sampling/monitoring stations are shown in Figure 1.3. 
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Figure 1.2 Lake Hancock (WBID 1623L) and Monitoring Stations 
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Figure 1.3 Lower Saddle Creek (WBID 1623K) and Monitoring Stations 
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1.3 Lake Hancock Historic Water Quality 

Concerns over water quality problems in Lake Hancock date back to the early 1950s. 

In this time-frame, Lake Hancock has been heavily impacted by man-made activities, 

including domestic waste and industrial wastewater treatment plant discharges from the cities 

of Lakeland, Winter Haven, and Auburndale, urban development, agricultural activities, 

wetland destruction, and phosphate mining. And as a result, the lake began and continued to 

develop high nutrient concentrations. Accumulation of organic matter within the lake began 

and continued to occur as a result of the hypereutrophic conditions and the continued 

herbicide treatments to control water hyacinths (ERD, 1999). 

A routine water quality monitoring program was initiated for Lake Hancock by Polk County in 

1984. A total of 32 separate surface water monitoring events were performed over a 16-year 

period from 1984-1999, for a mean of two monitoring events each year. The lake was 

characterized as having extremely elevated levels of pH, total nitrogen, total phosphorus, 

turbidity, and chlorophyll a.

According to Environmental Research and Design, Inc., (1999), measured concentrations of 

total nitrogen (TN) were 3-4 times greater than values observed in most urban lake systems. 

Total phosphorus (TP) concentrations were approximately 10-20 times greater and chlorophyll 

a concentrations approximately 5-10 times greater. A summary of mean water quality 

characteristic measured in Lake Hancock are displayed in Table 1.1. 

Table 1.1 Summary Statistics of Historical Water Quality in Lake 

 Hancock from 1985 to 1999 

Summary Statistics of Historical Water Quality Characteristics 

in Lake Hancock from 1985-1999 

Water Quality Variable Units 

Mean 

Value 

Minimum 

Value 

Maximum 

Value 

pH s.u. 9.18 7.38 10.13 

Dissolved Oxygen mg/L 8.6 0.9 15.7 

Temperature oC 24.0 15.6 34.3 

Specific Conductance μmho/cm 275 170 456 

Secchi Depth meters 0.2 0.1 0.6 

NH3-N mg/L 0.037 BDL 0.2 

Nox-N mg/L 0.01 BDL 0.05 

Organic N mg/L 5.95 1.47 15.4 

Total N mg/L 5.99 1.51 15.63 

Total P mg/L 0.63 1.05 2.87 

Turbidity NTU 44.6 4.3 104 

Color Pt-Co 58 27 100 

Chlorophyll a mg/m3 170 34 350 

Environmental Research and Design, Inc., December, 1999. 

BDL-Below Detectable Limits. 

Historically, water quality in Lake Hancock has been variable, particularly for the water quality 

variables pH, dissolved oxygen (DO), TN, TP, turbidity, and chlorophyll a. DO concentrations 

ranged near near-anoxic conditions to supersaturated conditions. TN concentrations varied 

from 1.51 to 15.63 milligrams per liter (mg/L). TP concentrations varied from .11 to 2.87 mg/L. 
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Variations in TN/TP rations also occurred in this time period. Based on historic ratios, the lake 

oscillated between nutrient-balanced conditions to phosphoruslimited and nitrogen limited conditions. A 25-fold difference in turbidity values was observed 

with a 10-fold difference observed for chlorophyll a. With a few exceptions, Lake Hancock 

has consistently exhibited hypereutrophic conditions from 1985 to 1999, with calculated 

annual mean trophic state index (TSI) values ranging from 67 to 101 and a mean TSI of 91. 

Note, TSI values were based entirely on chlorophyll a concentrations because the water 

column concentration of TP and measured Secchi depth were impacted heavily by the resuspension of bottom sediments as a result of consistent wind action (ERD, 1999) 

ERD also conducted surface water quality monitoring at three sites in Lake Hancock from 

March 2004-February 2005 in support of the Lake Hancock Outfall Treatment System 

Evaluation, funded by the Southwest Florida Water Management District (SWFWMD). See 

Table 1.2 for the means and ranges of water quality variables measured for Lake Hancock 

from 2004 to 2005. 

Table 1.2 Summary Statistics of Historical Water Quality in Lake 

 Hancock from March 2004 to February 2005 

Summary Statistics for Surface Water Samples Collected in Lake Hancock 

from March 2004 to February 2005 

Sample Site 1 Sample Site 2 Sample Site 3 

Water Qaulity Variable Units Mean Range Mean Range Mean Range 

Alkalinity mg/L 63.9 47.7-80.2 63.2 49.5-80.0 61 33.7-82.8 

NH3 mg/L 0.23 0.12-1.613 0.15 .010-0.760 0.15 .012-0.594 

NOx mg/L 0.02 0.005-0.171 0.02 0.005-0.147 0.03 0.005-0.237 

Dissolved Organic N mg/L 0.91 0.188-1.416 1.22 0.115-3.237 1.02 0.316-1.750 

Particulate N mg/L 2.91 1.590-5.544 2.45 0.192-4.713 2.48 0.555-4.384 

Total N mg/L 4.08 2.386-7.090 3.84 2.291-6.398 3.67 1.414-5.591 

SRP mg/L 0.10 0.001-0.358 0.10 0.001-0.357 0.12 0.001-0.374 

Dissolved Organic P mg/L 0.02 0.005-0.062 0.02 0.006-0.058 0.02 0.004-0.047 

Particulate P mg/L 0.35 0.140-0.691 0.33 0.121-0.604 0.29 0.090-0.569 

Total P mg/L 0.48 0.153-0.716 0.45 0.133-0.630 0.42 0.113-0.592 

Turbidity NTU 27.9 11.2-52.2 27.4 9.7-46.7 22.2 8.1-44.5 

TSS mg/L 71.3 16.0-164 66.9 14.4-150 52.4 13.3-157 

COD mg/L 137 53-278 132 51-294 117 55-224 

BOD mg/L 14.9 5.8-27.4 14.7 5.4-24.1 12.1 4.6-20.8 

Color Pt-Co 78 38-159 78 41-139 111 41-267 

Chlorophyll a mg/m3 383 103-800 369 119-747 265 60.7-462 

Calcium mg/L 22.7 17.8-27.2 22.7 16.5-26.7 22.4 16.5-27.9 

Chloride mg/L 16.1 3.9-22.6 14.8 4.6-22.9 15.6 4.2-22.5 

Chloride mg/L 16.1 3.9-22.6 14.8 4.6-22.9 15.6 4.2-22.5 

Environmental Research and Design, Inc., March, 2005. 

An extremely high degree of variability was observed in measured concentrations of all 

nitrogen species, particularly for ammonia and particulate nitrogen. Variability in measured 

values for ammonia cover approximately two orders of magnitude at the three monitoring 

sites, with approximately one order of magnitude between minimum and maximum values for 

particulate nitrogen at the three sites. In general, concentrations of measured nitrogen 

species were relatively similar between the three sites. Measured TN concentrations, which 
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ranged from 3.67-4.08 mg/L between the three monitoring sites, were extremely elevated, with 

values 2-3 times greater than commonly observed in Central Florida lakes (ERD, 2005). 

Particulate nitrogen was clearly the most dominant nitrogen species observed at each of the 

three sites, comprising 64-71 percent of the nitrogen present. The second most dominant 

species was dissolved organic nitrogen, which comprised 22-32 percent of the total nitrogen 

measured at the three sites. Substantially smaller contributions were observed for ammonia 

(4-6% of total nitrogen) and NOx (1% of total nitrogen) (ERD, 2005). 

Mean total phosphorus concentrations, which ranged from 0.42-0.48 mg/L at the three sites, 

were extremely high in value, compared with concentrations typically observed in Central 

Florida lakes. Particulate phosphorus appeared to be the dominant phosphorus species 

observed at each of the three monitoring sites, comprising 68-74 percent of the total 

phosphorus measured at each site. Soluble Reactive Phosphorus (SRP) was the second 

most dominant phosphorus species measured in Lake Hancock, comprising 21-28 percent of 

the total phosphorus measured. Dissolved organic phosphorus contributed approximately 4-5 

percent of the total phosphorus measured at each site (ERD, 2005). 

Extremely elevated concentrations of chlorophyll a were observed in Lake Hancock, with 

measured values approximately 10 times greater than commonly observed in urban lakes. 

Mean chlorophyll a concentrations measured were to be 3-4 times greater than concentrations 

commonly measured in hypereutrophic lakes such as Lake Apopka and Lake Jessup. 

Chlorophyll a concentrations were also highly variable at each of the three monitoring sites, 

with a factor of approximately 8 between minimum and maximum chlorophyll a values 

measured at each site (ERD, 2005). 

As a note, hurricanes Charley, Frances, and Jeanne occurred during the 2004 season in this 

region of the state of Florida which increased the flushing and dilution to Lake Hancock from 

tributary inflows. 

1.4 Lake Hancock Background Information 

The Lake Hancock watershed is located within west-central Polk County near the geographic 

center of peninsular Florida. Polk County is part of the highland area that trends along the 

north-south axis of peninsular Florida. Within the county there are three ridges separated by 

relatively flat lowland areas. The Lake Hancock watershed occupies the area between the 

Lakeland Ridge on the western boundary and Winter Haven Ridge along the eastern 

boundary (BCI Engineers and Scientists, Inc., 2005). Significant portions of the watershed 

have been mined for phosphate ore creating numerous spoil piles, clay settling area 

embankments, and water filled depressions and lakes. 

Lake Hancock receives inflow from primarily three major tributaries. Middle and Upper Saddle 

Creek originate to the north and east of the City of Lakeland and generally flow south through 

a swampy depression before turning into a creek and entering into the north shore of the lake. 

Lake Lena Run originates in Auburndale and enters Lake Hancock on the northeast side. 

Banana Lake, located about 1-mile northwest of Highland City, discharges into the Banana 

Lake Overflow Canal that enters the west side of the Lake. These three tributaries account for 

approximately 81 percent of the Lake Hancock watershed. The Eagle Lake system located 

below Lake Lena Run is a minor tributary that originates in the Eagle Lake area and enters 

Lake Hancock on the southeast side. Remaining areas of the watershed are contiguous to 

the lake. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 10

Climate in the Lake Hancock Basin is subtropical with humid, rainy summers, and dry mild 

winters. Average monthly temperatures range from 61°F in January to 82°F in July and 

August. About half of the annual rainfall occurs during the summer months of June through 

September. There has been an extended period of below normal rainfall in the Lake Hancock 

area and in central Florida generally since 1960. 

The Lake Hancock Watershed is underlain by a layer of sand, clay, and limestone, ranging in 

thickness from about 100 to 400 feet. Under the surficial layer is several thousand feet of 

limestone and dolomite. The formations comprising the watershed (Hammett, Snell, Joyner; 

USGS 1981) can be divided into three hydrogeologic units: (1) the surficial aquifer, (2) the 

secondary artesian aquifers and confining beds, and (3) the Floridian aquifer. The surficial 

aquifer is composed of sand, sandy clay, and pebble phosphate deposits, which in Polk 

County have been strip mined extensively. The thickness of this unit varies between 20 and 

130 feet. The secondary artesian aquifers and confining beds are composed of clay, 

dolomite, and limestone of the Hawthorn Formation and Tampa Limestone. The thickness of 

this unit varies between 50 and 150 feet. 

The Floridian aquifer consists of limestone and dolomite of the Suwannee Limestone, 

Ocala Limestone, and Avon Park Limestone. Drilling logs indicate that zones within the 

limestone and dolomite contain numerous cavities and honeycomb features that have resulted 

from dissolution of the carbonate rock by circulating ground water. Weaknesses in the 

geologic structure caused by dissolution are responsible for sinkhole collapses. In 1976, 

Ardaman and Associates, Inc., reported that between 1956 and 1975 more than 20 sinkhole 

collapses had occurred within two miles of Lake Hancock. 

Ground water in the surficial and the secondary artesian aquifers typically flow from the ridge 

areas to the streams and lakes of the lowland areas. However, the lowering of the Florida 

aquifer due to ground water withdrawals has created a downward movement of the surficial 

water into the secondary artesian in the area of Lake Hancock and the upper Peace River. 

A muck layer ranging in thickness from 1 to 4 feet covers the bottom of the lake. Underlying 

the muck are surficial deposits ranging from 9 to 17 feet in thickness which reside on top of 

the Bone Valley Formation containing phosphatic sands, gravels, and clays (Patton, 1980). 

Below the Bone Valley formation are Hawthorne limestones that have been dissolutioned by 

lateral movement of water to form the lake (BCI Engineers and Scientists, Inc., 2005). 

Mining for phosphate in the vicinity of Lake Hancock began between 1941 and 1952. No 

mining in the vicinity of Lake Hancock is evident in a 1941 aerial photograph of the Lake. By 

1952, aerial photographs indicate some areas approximately one mile to the northeast of the 

lake were being mined. Areas to the south of the lake showed mining activity by 1958. These 

areas were ultimately converted to clay settling areas. The 1968 aerials show active mining 

along the majority of the east side of the lake. Most of these mined areas have been 

reclaimed (BCI Engineers and Scientists, Inc., 2005). 

1.5 TMDL Background Information 

The TMDL report for Lake Hancock and Lower Saddle Creek is part of the implementation of 

the Department’s watershed management approach for restoring and protecting water 

resources and addressing Total Maximum Daily Load (TMDL) Program requirements. The 

watershed approach, which is implemented using a cyclical management process that rotates 

through the state’s fifty-two river basins over a five-year cycle, provides a framework for 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 11

implementing the requirements of the 1972 federal Clean Water Act and the 1999 Florida 

Watershed Restoration Act (Chapter 99-223, Laws of Florida). 

A TMDL represents the maximum amount of a given pollutant that a waterbody can assimilate 

and still meet the waterbody’s designated uses. A waterbody that does not meet its 

designated uses is defined as impaired. TMDLs must be developed and implemented for 

each of the state’s impaired waters, unless the impairment is documented to be a naturally 

occurring condition that cannot be abated by a TMDL or unless a management plan already in 

place is expected to correct the problem. 

The development and implementation of a Basin Management Action Plan, or BMAP, to 

reduce the amount of pollutants that caused the impairment will follow this TMDL Report. 

These activities will depend heavily on the active participation of the Southwest Florida Water 

Management District (SWFWMD), Polk County, local governments, local businesses, and 

other stakeholders. The Department will work with these organizations and individuals to 

undertake or continue reductions in the discharge of pollutants and achieve the established 

TMDLs for Lake Hancock and Lower Saddle Creek.
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 12

Chapter 2: STATEMENT OF WATER QUALITY 

PROBLEM 

2.1 Statutory Requirements and Rulemaking History 

Section 303(d) of the federal Clean Water Act requires states to submit to the EPA a list of 

surface waters that do not meet applicable water quality standards (impaired waters) and 

establish a TMDL for each pollutant causing the impairment of the listed waters on a 

schedule. The Department has developed such lists, commonly referred to as 303(d) lists, 

since 1992. The list of impaired waters in each basin, referred to as the Verified List, is also 

required by the Florid Watershed Restoration Act (Subsection 403.067[4)] Florida Statutes 

[F.S.]), and the state’s 303(d) list is amended annually to include basin updates. 

Florida’s 1998 303(d) list included 52 waterbodies in the Peace River Planning Unit with 11 of 

those waterbodies in the Lake Hancock Basin. However, the FWRA (Section 403.067, F.S.) 

stated that all previous Florida 303(d) lists were for planning purposes only and directed the 

Department to develop, and adopt by rule, a new science-based methodology to identify 

impaired waters. In April 2001, the Environmental Regulation Commission adopted the new 

methodology as Chapter 62-303, F.A.C., (Identification of Impaired Surface Waters Rule, or 

IWR).

2.2 Information on Verified Impairment 

The Department used the IWR methodology to assess water quality in Lake Hancock and 

Lower Saddle Creek, and both the lake and the creek were verified impaired for nutrients and 

dissolved oxygen (DO). Lake Hancock was verified as impaired in 2003 for nutrients based 

on an annual average Trophic State Index (TSI) value of 83.5, which exceeded the IWR 

threshold value of 60 during the verification period (the Verified Period for the Group 3 basins 

is from January 1, 1997 to June 30, 2004). The median values for Total Nitrogen (TN), Total 

Phosphorus (TP), and biochemical oxygen demand (BOD) for the lake for the verified period 

were 4.46, 0.49, and 9.9 mg/L, respectively, which are significantly higher than the 70th

percentile for Florida lakes (see Table 2.1). 

Table 2.1 Screening Level Values (70th percentile) Based on STORET 

 Data from 1979 to 1987 

Waterbody Type BOD 5 Day 

(mg/L)

Total Nitrogen 

(mg/L) 

Total Phosphorus 

(mg/L)

Stream 2.0 1.6 .22 

Lake 2.9 1.7 .11 

Estuary 2.1 1.0 .19 

Source: Friedemann, F., and Hand, J., July 1989. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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The TSI is calculated based on concentrations of TP, TN, and chlorophyll a as follows: 

TSI Formula 

CHLATSI = 16.8 + 14.4 * LN(Chl a) Chlorophyll a in μg/L 

TNTSI = 56 + 19.8 * LN(N) Nitrogen in mg/L 

TN2TSI = 10 * [5.96 + 2.15 * LN(N + 0.0001)] Phosphorus in mg/L 

TPTSI = 18.6 * LN(P * 1000) – 18.4 

TP2TSI = 10 * [2.36 * LN(P * 1000) – 2.38] 

If N/P > 30, then NUTRTSI = TP2TSI 

If N/P < 10, then NUTRTSI = TN2TSI 

if 10< N/P < 30, then NUTRTSI = (TPTSI + TNTSI)/2 

TSI = (CHLATSI + NUTRTSI)/2 Note: TSI has no units 

The lake is listed as impaired for DO because, from 1997 to 2004, more than 10 percent of the 

DO results did not meet the freshwater DO criterion of 5 mg/L. Following the IWR 

methodology, there were 27 DO exceedances out of 140 samples (19.3 percent exceedance 

rate). 

Lower Saddle Creek was verified as impaired for nutrients based on elevated seasonal and 

annual average chlorophyll a values that exceeded the IWR listing threshold of 20 μg/L for 

freshwater streams. Annual average chlorophyll a values for the Verified Period (years 1997 

to 2003) were 107, 89.1, 141.1, 73.5, 102.6, 93.2, and 163.5 μ/g/L, respectively. The median 

TN, TP, and BOD values for the creek for the verified period were 2.40, 0.40, and 6.5 mg/L, 

respectively. The creek was verified as impaired for DO because, from 1997 to 2004, more 

than 10 percent of the DO results did not meet the freshwater DO criterion of 5 mg/L. 

Following the IWR methodology, there were 46 DO exceedances out of 130 samples (35.4 

percent exceedance rate). 

For modeling purposes, the analyses of the eutrophication-related data for Lake Hancock 

used “all” of the available data from 1984 – 2004 for which records of TP, TN, and chlorophyll 

a were sufficient to calculate seasonal annual average conditions. However, to calculate the 

TSI for a given year under the IWR, there must be at least one sample of TN, TP, and 

chlorophyll a taken at the same time period in each season of the year. The absence of data 

from all four seasons for many years in the planning and verified periods resulted in 2003 as 

the only year with sufficient data to calculate a TSI for Lake Hancock for assessing impairment 

following the IWR methodology. 

Figure 2.1 displays annual average TSI values for all data from 1984 to 2004 (includes 

Lakewatch data) and the IWR verified period TSI value from 2003 (does not include 

Lakewatch data). Additionally, as the verified period ends in June of 2004, annual averages 

were not calculated for 2004 during the IWR assessment for the Lake Hancock Basin, but are 

displayed in Figure 2.1 for review. In 2003, the seasonal annual average TSI value of 83.5 

exceeded the IWR threshold value of 60. Exceeding 60 in any one year of the verified period 

is sufficient in identifying a lake as being impaired for nutrients. Annual average color values 

for the verified period for the lake were 53.3 (1997), 73.3 (1998), 240 (1999), 108.3 (2002), 

and 100.3 (2003). The annual average color value for years in the verified period was 115.04.
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 14

Monthly and annual average TN results for Lake Hancock from 1992 to 2004 are displayed in 

Figures 2.2 and 2.3, respectively. Monthly and annual average TP results from 1992 to 2004 

are displayed in Figures 2.4 and 2.5. Monthly and annual average chlorophyll a results from 

1992 to 2004 are displayed in Figures 2.6 and 2.7. Monthly and annual average DO results 

from 1992 to 2004 are displayed in Figures 2.8 and 2.9. Monthly and annual average TN 

results for Lower Saddle Creek from 1992 to 2004 are displayed in Figures 2.10 and 2.11,

respectively. Individual station and annual average TP results from 1992 to 2004 are 

displayed in Figures 2.12 and 2.13. Monthly and annual average chlorophyll a results from 

1992 to 2004 are displayed in Figures 2.14 and 2.15. Monthly and annual average DO 

results for Lower Saddle Creek from 1992 to 2004 are displayed in Figures 2.16 and 2.17. 

Values from all stations for TN for Lake Hancock from 1992 to 2004 were typically highest 

during the months of February, May, August, and November. Values for TP were highest 

during the months of February, May, and November. Values for chlorophyll a were highest 

during the months of February, May, and August. Values for DO from 1992 to 2003 were 

typically lowest during the months of May and August. 

For Lower Saddle Creek from 1992 to 2004, TN, TP and chlorophyll a values were 

consistently high through-out all months/seasons for the period of record. However, values 

from all stations for TN appeared to typically be highest during the months of February, July, 

August, and October. Values for TP were highest during the months of April, August, October 

and November. Values for chlorophyll a from 1995 to 2004 were highest during the months of 

April, August, and November. Values for DO from 1992 to 2004 were lowest during the 

months of April, May, July, August, and October. 

The months of August and November appear to show the strongest relationship in terms of 

consistently having high monthly values for TN, TP, and chlorophyll a between the lake and 

creek. The months of May and August appear to show the strongest relationship in regard to 

low DO values for the lake and the creek. The fluctuations in water quality values appear to 

be quite variable between the months and seasons for the lake and the creek. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 15

Lake Hancock - WBID 1623L 

Trophic State Index (TSI) Annual Mean Results 1984-2004

0

20

40

60

80

100

120

1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004

Year

TSI 

All Results-WBID 1623L IWR Results-WBID 1623L

Figure 2.1 TSI Results for Lake Hancock Calculated from Annual Average 

 Concentrations of TP, TN, and Chlorophyll a from 1984 to 2004 

Lake Hancock - WBID 1623L 

Total Nitrogen Results 1992-2004

0

2

4

6

8

10

12

14

Jan-92 Jan-93 Jan-94 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04

Date

TN (mg/L)

21FLPOLKHANCOCK A 21FLPOLKHANCOCK B 21FLPOLKHANCOCK C

21FLPOLKHANCOCK D 21FLPOLKHANCOCK1 21FLPOLKHANCOCK H 2-62

21FLSWFDSTA0192 21FLTPA 25020276

Figure 2.2 Total Nitrogen Monthly Results for Lake Hancock from 1992 to 2004 
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 16

Lake Hancock - WBID 1623L 

Total Nitrogen Annual Mean Results 1992-2004

0

1

2

3

4

5

6

7

8

9

10

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

TN (mg/L)

All Stations-WBID 1623L

Figure 2.3 Total Nitrogen Annual Mean Results for Lake Hancock from 1992 to 2004 

Lake Hancock - WBID 1623L 

Total Phosphorus Results 1992-2004

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

Jan-92 Jan-93 Jan-94 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04

Date

TP (mg/L)

21FLPOLKHANCOCK A 21FLPOLKHANCOCK B 21FLPOLKHANCOCK C

21FLPOLKHANCOCK D 21FLPOLKHANCOCK1 21FLPOLKHANCOCK H 2-62

21FLSWFDSTA0192 21FLTPA 25020276

Figure 

2.4 Total Phosphorus Monthly Results for Lake Hancock from 1992 to 2004 
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 17

Lake Hancock - WBID 1623L 

Total Phosphorus Annual Mean Results 1992-2004

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

TP (mg/L)

All Stations-WBID 1623L

Figure 2.5 Total Phosphorus Annual Mean Results for Lake Hancock from 1992 to 

2004 

Lake Hancock - WBID 1623L 

Chlorophyll a Results 1992-2004

0

50

100

150

200

250

300

350

400

450

500

Jan-92 Jan-93 Jan-94 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04

Date

Chorophyll 

a (

μg/L)

21FLPOLKHANCOCK A 21FLPOLKHANCOCK B 21FLPOLKHANCOCK C

21FLPOLKHANCOCK D 21FLPOLKHANCOCK 9-62 21FLPOLKHANCOCK1

21FLSWFDSTA0192 21FLTPA 25020276

Figure 

2.6 Chlorophyll a Monthly Results for Lake Hancock from 1992 to 2004
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 18

Lake Hancock - WBID 1623L 

Chlorophyll a Annual Mean Results 1992-2004

0

50

100

150

200

250

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

Chlorophyll 

a ( g/L)

All Stations-WBID 1623L

Figure 2.7 Chlorophyll a Annual Mean Results for Lake Hancock from 1992 to 2004 

Lake Hancock - WBID 1623L 

Dissolved Oxygen Results 1992-2004

0

2

4

6

8

10

12

14

16

18

Jan-92 Jan-93 Jan-94 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04

Date

DO (mg/L)

21FLPOLKHANCOCK A 21FLPOLKHANCOCK B 21FLPOLKHANCOCK C

21FLPOLKHANCOCK D 21FLPOLKHANCOCK1 21FLPOLKHANCOCK H-9-63

21FLSWFDSTA0192 21FLTPA 25020276 DO Freshwater Criterion

Figure 2.8 Dissolved Oxygen Monthly Results for Lake Hancock from 1992 to 2004 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 19

Lake Hancock - WBID 1623L 

Dissolved Oxygen Annual Mean Results 1992-2004

0

2

4

6

8

10

12

14

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Year

DO (mg/L)

All Stations-WBID 1623L DO Freshwater Criterion

Figure 2.9 Dissolved Oxygen Annual Mean Results for Lake Hancock from 1992 to 

2004 

Lower Saddle Creek - WBID 1623K 

Total Nitrogen Results 1992-2004

0

1

2

3

4

5

6

7

8

9

10

Jan-92 Jan-93 Jan-94 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04

Date

TN (mg/L)

21FLPOLKP.C. CANAL9 21FLSWFDFLO 37 72 0 21FLSWFDFLO0038 112WRD 02294491

Figure 2.10 Total Nitrogen Monthly Results for Lower Saddle Creek from 1992 

 to 2004 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 20

Lower Saddle Creek - WBID 1623K

Total Nitrogen Annual Mean Results 1992-2004

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

7.0

1992 1993 1994 1995 1996 1998 1999 2000 2001 2002 2003 2004

Year

TN (mg/L)

All Stations-WBID 1623K

Figure 2.11 Total Nitrogen Annual Mean Results for Lower Saddle Creek 

 from 1992 to 2004 

Lower Saddle Creek - WBID 1623K 

Total Phosphorus Results 1992-2004

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Jan-92 Jan-93 Jan-94 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04

Date

TP (mg/L)

21FLPOLKP.C. CANAL9 21FLSWFDFLO 37 72 0 21FLSWFDFLO0038

21FLTPA 27552158149358 112WRD 02294491

Figure 2.12 Total Phosphorus Monthly Results for Lower Saddle Creek from 1992 

 to 2004 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 21

Lower Saddle Creek - WBID 1623K 

Total Phosphorus Annual Mean Results 1992-2004

0.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

2.00

2.25

2.50

2.75

3.00

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

TP (mg/L)

All Stations-WBID 1623K

Figure 2.13 Total Phosphorus Annual Mean Results for Lower Saddle Creek 

 from 1992 to 2004 

Lower Saddle Creek - WBID 1623K 

Chlorophyll a Results 1995-2004

0

20

40

60

80

100

120

140

160

180

Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04

Date

Chlorophyll 

a ( g/L)

21FLPOLKP.C. CANAL9 21FLSWFDFLO 37 72 0 21FLTPA 27552158149358

Figure 2.14 Chlorophyll a Monthly Results for Lower Saddle Creek from 1995 to 2004 
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 22

Lower Saddle Creek - WBID 1623K 

Chlorophyll a Annual Mean Results 1995-2004

0

20

40

60

80

100

120

140

160

180

200

1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

Chlorophyll 

a ( g/L)

All Stations-WBID 1623K

Figure 2.15 Chlorophyll a Annual Mean Results for Lower Saddle Creek 

 from 1995 to 2004 

Lower Saddle Creek - WBID 1623K 

Dissolved Oxygen Results 1992-2004

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

Jan-92 Jan-93 Jan-94 Jan-95 Jan-96 Jan-97 Jan-98 Jan-99 Jan-00 Jan-01 Jan-02 Jan-03 Jan-04

Date

DO (mg/L)

21FLPOLKP.C. CANAL9 21FLSWFDFLO 37 72 0 21FLSWFDFLO0038

21FLTPA 27552158149358 112WRD 02294491 DO Freshwater Criterion

Figure 2.16 Dissolved Oxygen Monthly Results for Lower Saddle Creek from 1992 

 to 2004 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 23

Lower Saddle Creek - WBID 1623K 

Dissolved Oxygen Annual Mean Results 1992-2004

0

1

2

3

4

5

6

7

8

9

10

11

12

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004

Year

DO (mg/L)

All Stations-WBID 1623K DO Freshwater Criterion

Figure 2.17 Dissolved Oxygen Annual Mean Results for Lower Saddle Creek 

 from 1992 to 2004

Table 2.2 provides summary statistics for the lake and creek for TN, TP, chlorophyll a, and 

DO from 1992 to 2004. Individual water quality measurements for TN, TP, chlorophyll a, and 

DO used in the assessment are provided in Appendix B. 

Table 2.2 Water Quality Summary Statistics for TN, TP, Chlorophyll a, and DO from 1992 

to 2004 for Lake Hancock (WBID 1623L) and Lower Saddle Creek (WBID1623K)

Waterbody Water Variable # of 

Samples Minimum Mean Median Maximum

Lake Hancock Total Nitrogen 

(mg/L) 134 1.19 4.57 4.40 12.03 

Lake Hancock Total Phosphorus 

(mg/L) 135 0.04 0.52 0.49 1.01 

Lake Hancock Chlorophyll a 

(μg/L) 77 16.02 175.15 148 558.00 

Lake Hancock Dissolved Oxygen 

(mg/L) 140 0.38 8.26 8.43 15.70 

Lower Saddle Cr. Total Nitrogen 

(mg/L) 75 0.39 2.95 2.50 11.02 

Lower Saddle Cr. Total Phosphorus 

(mg/L) 134 0.01 0.63 0.45 10.50 

Lower Saddle Cr. Chlorophyll a 

(μg/L) 111 1.00 101.18 79.30 612.00 

Lower Saddle Cr. Dissolved Oxygen 

(mg/L) 130 0.31 6.08 6.26 15.56 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 24

As part of the listing process, the Department attempts to identify the limiting nutrient or 

nutrients for the impaired waterbody. The limiting nutrient, generally nitrogen or phosphorus, 

is defined as the nutrient that limits plant growth when it is not available in sufficient quantities. 

A limiting nutrient is a chemical that is necessary for plant growth, but available in quantities 

smaller than those needed for algae, represented by chlorophyll a, and macrophytes to grow. 

Once the limiting nutrient in a waterbody is exhausted, algae stop growing. If more of the 

limiting nutrient is added, larger algal populations will result until nutrients or other 

environmental factors again limit their growth. In Florida waterbodies, nitrogen and 

phosphorus are most often the limiting nutrients 

The following method is used to identify the limiting nutrient(s) in streams and lakes: 

• The ratios of TN to TP are calculated for each paired value of TN and TP (per sampling 

event) collected during the verified period. If a waterbody segment TN or TP median values 

exceed the appropriate screening levels, the nutrient exceeding the screening level may be 

identified as a potential pollutant causing impairment. The median values are then compared 

with the screening levels for the appropriate waterbody type. The screening levels represent 

the 70th percentile value of data collected from streams, lakes, or estuaries in Florida (see

Table 2.1). 

• The individual ratios over the entire verified period (i.e., January 1997 to June 2004) are 

evaluated to determine the limiting nutrient(s). If all the sampling event ratios are less than 

10, nitrogen is identified as the limiting nutrient, and if all the ratios are greater than 30, 

phosphorus is identified as the limiting nutrient. Both nitrogen and phosphorus are identified 

as limiting nutrients if the ratios are between 10 and 30. For Lake Hancock and Lower Saddle 

Creek the median TN/TP ratios are 9.49 and 7.22, respectively, for the verified period, 

suggesting that nitrogen is the limiting nutrient in the lake and creek. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 25

Chapter 3. DESCRIPTION OF APPLICABLE WATER 

QUALITY STANDARDS AND TARGETS 

3.1 Classification of the Waterbody and Criteria Applicable to the TMDL 

Florida’s surface water is protected for five designated use classifications, as follows: 

Class I Potable water supplies 

Class II Shellfish propagation or harvesting 

Class III Recreation, propagation, and maintenance of a healthy, wellbalanced population of fish and wildlife 

Class IV Agricultural water supplies 

Class V Navigation, utility, and industrial use (there are no state waters 

currently in this class) 

Lake Hancock and Lower Saddle Creek are classified as Class III freshwater waterbodies, 

with a designated use of recreation, propagation and maintenance of a healthy, well-balanced 

population of fish and wildlife. The Class III water quality criterion applicable to the observed 

impairments for Lake Hancock and Lower Saddle Creek are the state of Florida’s narrative 

nutrient criterion [Rule 62-302.530(48)(b), FAC] and dissolved oxygen criterion [Rule 62-

302.530(31), F.A.C]. 

3.2 Dissolved Oxygen Criterion for Lakes and Streams 

The Class III freshwater criterion for dissolved oxygen (DO) for lakes and streams, established 

by Subsection 62-302.530(31), F.A.C., states that DO shall not be less than 5.0 mg/L and that 

normal daily and seasonal fluctuations above these levels shall be maintained. 

As required by the IWR, the Department must identify the pollutants causing or contributing to 

DO impairment. If a waterbody segment has a sufficient number of DO exceedances for 

placement on the Verified List and nutrients is on the Verified List, based on exceedances of 

the IWR TSI or chlorophyll a thresholds, then “nutrients” is identified as a pollutant contributing 

to DO exceedances. The Department also applies the following analysis to identify the 

pollutant(s) contributing to DO exceedances: 

• The waterbody segment median values for biochemical oxygen demand (BOD), total 

nitrogen (TN), and total phosphorus (TP) are determined for the verified period (i.e., January 

1997 to June 2004). 

• The median values are then compared with the screening levels for the appropriate 

waterbody type. The screening levels represent the 70th percentile value of data collected 

from streams, lakes, or estuaries in Florida (Table 2.2). 

• If a waterbody segment median BOD value exceeds the screening level, BOD is identified as 

a pollutant contributing to DO exceedances. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 26

• If a waterbody segment TN or TP median values exceed the appropriate screening levels, 

and there are insufficient data to assess nutrients using the IWR TSI or chlorophyll a

thresholds, the nutrient exceeding the screening level may be identified as a pollutant 

contributing to the exceedances. As noted in Chapter 2, Section 2.2, the median values for 

TN, TP, and BOD for the lake for the verified period exceeded the 70th percentile for Florida 

lakes. 

For Lake Hancock and Lower Saddle Creek, low DO concentrations appear to be related to 

excessive nutrient loadings. During the verified period, monthly and annual average 

chlorophyll a concentrations for the lake and the creek were well above the IWR’s thresholds 

for nutrient impairment. 

In addition to causing excessive growth of algae, nutrient enrichment of a waterbody can lead 

to widely varying DO levels and low DO concentrations in the water column. Depressed DO 

concentrations may be caused by several factors, including the decay of oxygen demanding 

waste from point and non-point sources, conversion of ammonia to nitrate in the nitrification 

process (where oxygen is consumed by aerobic nitrifying bacteria), macrophyte respiration, 

excessive epiphyte or floating macrophyte growth blocking light to submerged aquatic 

vegetation, and sediment oxygen demand (SOD). Nutrients may also influence DO levels 

indirectly. Algal populations can increase rapidly if nutrients are available resulting in the 

production of oxygen from the process of photosynthesis during daylight hours. Algal 

respiration or consumption of oxygen from the water column at night may also result in large 

diurnal fluctuations of DO in the water column. A fraction of any increased algal biomass may 

also become part of the organic material that will be broken down by microbes or settle to the 

bottom. Processes that consume oxygen from the water column such as microbial breakdown 

of organic material and SOD are fairly constant over the short term. 

Although nitrogen appears to be the limiting nutrient for the lake and the creek, reductions in 

TN and TP loadings would be expected to result in decreases in chlorophyll a. Reductions in 

TN and TP loadings to the lake are also expected to result in additional benefits for other 

parameters contributing to the impairment including DO and biochemical oxygen demand 

(BOD). The reduction in nitrogen and phosphorus loads should result in lower algal biomass 

levels in the water column, and lower algal biomass levels will result in smaller diurnal 

fluctuations in DO and less algal-based total suspended solids and reduced BOD.

Water quality in Lower Saddle Creek is directly influenced by the water quality in Lake 

Hancock. As such, the high nutrient values in the lake are linked to the excessive algal 

growth that led to the lake and the creek being impaired for low DO. As a result of this direct 

influence, it is anticipated that achieving the TMDL for nutrients in Lake Hancock will result in 

achieving water quality standards in Lower Saddle Creek. Therefore, the DO impairment for 

the lake and the DO and nutrient impairment for the creek are addressed by the nutrient 

TMDL for Lake Hancock.

3.3 Interpretation of the Narrative Nutrient Criteria for Lakes and Streams 

Florida’s nutrient criterion is narrative only — nutrient concentrations of a body of water shall 

not be altered so as to cause an imbalance in natural populations of aquatic flora or fauna. 

Accordingly, a nutrient-related target was needed to represent levels at which an imbalance in 

flora or fauna is expected to occur. While the IWR provides a threshold for nutrient 

impairment for lakes based on annual average TSI levels, these thresholds are not standards 

and are not required to be used as the nutrient-related water quality target for TMDLs. In 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 27

recognition that the IWR thresholds were developed using statewide average conditions, the 

IWR (Subsection 62-303.450, F.A.C.) specifically allows the use of alternative, site-specific 

thresholds that more accurately reflect conditions beyond which an imbalance in flora or fauna 

occurs in the waterbody. 

The TSI originally developed by R. E. Carlson (1977) was calculated based on Secchi depth, 

chlorophyll concentration, and total phosphorus concentration and was used to describe a 

lake’s trophic state. Carlson’s TSI was developed based on the assumption that the lakes 

were all phosphorus limited. In Florida, because the local geology produced a phosphorus 

rich soil, nitrogen can be the sole or co-limiting factor for phytoplankton in some lakes. In 

addition, because of the existence of dark-water lakes in the state, using Secchi depth as an 

index to represent lake trophic state can produce misleading results. 

 Therefore, the TSI was revised to be based on total nitrogen, total phosphorus, and 

 chlorophyll a concentrations. This revised calculation for TSI now contains a TN -TSI, 

 TP -TSI, and chlorophyll a -TSI. As a result, there are three different ways of calculating a 

 final in-lake TSI. If the TN to TP ratio is equal to or greater than 30, the lake is considered 

 phosphorus limited and the final TSI is the average of the TP -TSI and the chlorophyll a - TSI. 

 If the TN to TP ratio is 10 or less, the lake is considered nitrogen limited and the final TSI 

 is the average of the TN -TSI and the chlorophyll a -TSI. If the TN to TP ratio is between 10 

 and 30, the lake is considered co-limited and the final TSI is the result of averaging the 

 chlorophyll a -TSI with the average of the TN and TP TSI’s. 

The Florida-specific TSI for Lakes was determined based on the analysis of data from 313 

Florida lakes. The index was adjusted so that a chlorophyll a concentration of 20 μg/L was 

equal to a chlorophyll a -TSI value of 60. The final TSI for any lake may be higher or lower 

than 60 depending on the TN -TSI and the TP -TSI values. A TSI of 60 was then set as the 

threshold for nutrient impairment for most lakes (for those with a color higher than 40 platinum 

cobalt units) because, generally, the phytoplankton may switch to communities dominated by 

blue-green algae at chlorophyll a levels above 20 μg/L. These blue-green algae are often an 

unfavorable food source to zooplankton and many other aquatic animals. Some blue-green 

algae may even produce toxins, which could be harmful to fish and other animals. In addition, 

excessive growth of phytoplankton and the subsequent death of these algae may consume 

large quantities of dissolved oxygen and result in anaerobic condition in lakes, which makes 

conditions in the impacted lake unfavorable for fish and other wildlife. All of these processes 

may negatively impact the health and balance of native fauna and flora. 

Because of the amazing diversity and productivity of Florida lakes, some lakes have a natural 

background TSI that is different from 60. In recognition of this natural variation, the IWR 

allows for the use of a lower TSI (40) in very clear lakes, a higher TSI if paleolimnological data 

indicate the lake was naturally above 60, and the development of site-specific thresholds that 

better represent the levels at which nutrient impairment occurs. For the Lake Hancock and 

Lower Saddle Creek TMDLs, the Department applied the Watershed Assessment Model 

(WAM) (Soil and Water Engineering Technology, Inc., 2005) and the BATHTUB model 

(Quantitative Environmental Analysis, LLC, 2005) to simulate water quality discharges and 

eutrophication processes to determine the appropriate nutrient loadings. The WAM model 

was used to estimate the natural background TSI by setting land uses to a mixture of natural 

land cover. The loadings were then input to the BATHTUB lake model to calculate a natural 

background TSI value. Once the natural background TSI was determined, then an increase of 

5 TSI units above natural background was used as the water quality target for the TMDL. The 

estimated natural background TSI for Lake Hancock is 69.4, with a target TSI of 74.4.
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 28

3.3.1 Criteria Definitions

Chlorophyll a

Chlorophyll is a green pigment found in plants and is an essential component in the process of 

converting light energy into chemical energy. Chlorophyll is capable of channeling the energy 

of sunlight into chemical energy through the process of photosynthesis. In photosynthesis, 

the energy absorbed by chlorophyll transforms carbon dioxide (CO2) and water (H2O) into 

carbohydrates and oxygen (O2). The chemical energy stored by photosynthesis in 

carbohydrates drives biochemical reactions in nearly all living organisms. Thus, chlorophyll is 

at the center of the photosynthetic oxidation-reduction reaction between carbon dioxide and 

water. 

There are several types of chlorophyll; however, the predominant form is chlorophyll a. The 

measurement of chlorophyll a in a water sample is a useful indicator of phytoplankton 

biomass, especially when used in conjunction with analysis concerning algal growth potential 

and species abundance. The greater the abundance of chlorophyll a, typically the greater the 

abundance of algae. Algae are the primary producers in the aquatic food web, and thus are 

very important in characterizing the productivity of lakes and streams. As noted earlier, 

chlorophyll a measurements are also used to estimate the trophic conditions of lakes and 

lentic waters. 

Biochemical Oxygen Demand (BOD) 

BOD values are a measure of food for naturally occurring microorganisms. When food is 

introduced, naturally occurring microorganisms begin to multiply rapidly at an exponential rate, 

resulting in the reduction of dissolved oxygen in the water. After all of the food is consumed, 

they die and become food for protozoa, which in turn die off and become food for rotifers and 

crustaceans. BOD provides a quantitative measure of the amount of oxygen required to 

maintain the growth and activities of the microbial organisms responsible for the aerobic 

digestion of organic and putrescible matter. High BOD demand is a major contributor to DO 

depletion and is normally indicative of poor water quality.

Dissolved Oxygen (DO) 

Dissolved oxygen is an essential component in the aquatic environment. Like terrestrial 

species, fish and other aquatic organisms need oxygen to survive. As an example, for fish, as 

water moves through the gills, microscopic bubbles of oxygen gas in the water (called 

dissolved oxygen) are transferred from the water to the blood stream. Like any other gas 

diffusion process, the transfer of DO is efficient only above certain concentrations. DO is also 

important for many chemical reactions that are important for a healthy functioning waterbody. 

DO is produced during photosynthesis and consumed during respiration and decomposition. 

DO is also produced where water and air meet (i.e., diffusion of air molecules into the water 

from wind action, surface water turbulence, inflowing streams etc.) 

 

Nitrogen Total as N (TN) 

Total nitrogen is the combined measurement of nitrate (NO3

-

), nitrite (NO2

-

), ammonia (NH3 + 

NH4

+

), and organic nitrogen (NH2) found in water. Nitrogen compounds function as important 

nutrients to many aquatic organisms and are essential to the chemical processes that exist 

between land, air, and water. The most readily bioavailable forms of nitrogen are ammonia 

and nitrate. These compounds, in conjunction with other nutrients, serve as an important 

base for primary productivity. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 29

The major source of excessive amounts of nitrogen in surface water are the effluent from 

municipal treatment plants and runoff from agricultural sites. When nutrient concentrations 

consistently exceed natural levels, the resulting nutrient imbalance can cause undesirable 

changes in a waterbody’s biological community and drive an aquatic system into an 

accelerated rate of eutrophication. Usually, the eutrophication process is observed as a 

change in the structure of the algal community and includes severe algal blooms that may 

cover large areas for extended periods. Large algal blooms are generally followed by a 

depletion in dissolved oxygen concentrations as a result of algal decomposition. 

Phosphorus Total as P (TP) 

Phosphorus is one of the primary nutrients that regulates algal and macrophyte growth in 

natural waters, particularly in fresh water. Phosphate, the form in which almost all phosphorus 

is found in the water column, can enter the aquatic environment in a number of ways. Natural 

processes transport phosphate to water through atmospheric deposition, ground water 

percolation, and terrestrial runoff. Municipal treatment plants, industries, agriculture, and 

domestic activities also contribute to phosphate loading through direct discharge and natural 

transport mechanisms. The very high levels of phosphorus in some of Florida’s streams and 

estuaries are usually caused by phosphate mining and fertilizer processing activities. 

High phosphorus concentrations are frequently responsible for accelerating the process of 

eutrophication, or accelerated aging, of a waterbody. Once phosphorus and other important 

nutrients enter the ecosystem, they are extremely difficult to remove. They become tied up in 

biomass or deposited in sediments. Nutrients, particularly phosphates, deposited in 

sediments generally are redistributed to the water column. This type of cycling compounds 

the difficulty of halting the eutrophication process. 

3.4 Paleolimnological Information for the Lake Hancock Basin 

Paleolimnological methods can be used to identify baseline limnological conditions and to 

assess anthropogenic changes in lakes that lack historical limnological data. The lack of 

historical water quality data makes it difficult to document past changes in the trophic status of 

numerous Florida lakes. The absence of long-term limnological data makes it difficult to 

document the timing and magnitude of anthropenic changes in most of Florida’s lakes. Thus, 

paleolimnological studies are very important in yielding information on historical trophic 

conditions. Three lakes in the modeled Lake Hancock Basin (Hancock, Hollingsworth, and 

Parker) have historical limnological information available and are briefly discussed below. 

Lake Hancock 

In 2002, a paleolimnological study of Lake Hancock was performed by the University of 

Florida (Brenner, Whitmore, Curtis, and Hodell, 2002). Two sediment cores were collected 

from the lake to evaluate historical trophic state changes in the basin. Sediment diatom 

assemblages and a variety of nutrient-related variables (density, carbon, nitrogen, 

phosphorus, and organic matter) were measured. The trophic state was inferred by using 

models that relate diatom assemblages to water quality variables in Florida lakes. Although 

age-depth relations for the cores could not be established using radiometric methods, 

unsupported Lead210 activities in the cores suggested that the upper deposits in the cores 

accumulated within the last 100 years. 

Diatom data from one of the core samples suggest that the lake has been hypereutrophic and 

there has been no directional change in trophic status over time represented by the top 60 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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centimeters (cm) of the core (<100 years). Limnetic total phosphorus and chlorophyll a from 

the other core sample indicates a shift from eutrophic to hypereutrophic conditions above 28 

cm. This suggests that the lake has been hypereutrophic for the last 100 years (or perhaps 

less) and less productive (eutrophic) beyond that time period, as inferred from sediments that 

are greater than 100 years old (Brenner, Whitmore, Curtis, and Hodell, 2002). Thus, the 

results indicate that the trophic state of the lake was historically mesotrophic to eutrophic prior 

to becoming hypereutrophic. The diatom assemblages and Lead210 dating suggest that this 

shift probably occurred within the last 100 years, which would temporally correspond with 

anthropogenic disturbances in the watershed and surrounding air-shed. 

However, the authors note that the type of sediment accumulation on the bottom of Lake 

Hancock makes it a less than ideal archive of paleolimnological information and that diatom 

assemblages be used only to discern general trends rather than identify specific inference 

values (i.e., used with caution for this specific lake). 

Lake Hollingsworth (Banana Lake Sub-basin) 

Similar to most of the lakes located in the Lake Hancock and Saddle Creek basin, Lake 

Hollingsworth lies in phosphate rich central Florida. In 1899, it was reported that the state’s 

largest strawberry farm was operating near the lake. In the early 1900s, residential 

development began on the northwest portion of the lake. The 1920s marked additional changes 

in land use with the groundbreaking for Florida Southern College and more residents. In the 

1950s, citrus groves were prominent in the area, but were steadily being replaced for phosphate 

mining activities. By the mid-1970s, citrus groves had been replaced by residential and 

extractive land uses. Today, nearly the entire lake watershed is developed. 

The earliest limnological investigations on Lake Hollingsworth suggest that hypereutrophic 

conditions already existed by the late 1960s (Chew, 1974; Huber et al., 1982). According to 

Brenner et al., (1995), historical total phosphorus inferences based on diatom analyses from 

lake-core samples indicated that Lake Hollingsworth was naturally eutrophic. The limnetic 

phosphorus concentrations increased in the middle of the 20th century, with very high 

phosphorus levels occurring between the 1950s and 1970s. The historical perspective provided 

by the paleolimnological data demonstrates that Lake Hollingsworth was naturally eutrophic, but 

became hypereutrophic as a consequence of anthropogenic disturbances. 

Lake Parker (Lake Parker Sub-basin) 

Results from a case study conducted by Brenner, Whitmore, Flannery, and Binford (1993), 

showed that Lake Parker has displayed statistically significant increases in limnetic total 

phosphorus and chlorophyll a concentrations since the 1920s. The study evaluated sediment 

diatom assemblages to infer former water quality. Sediment diatoms are powerful bioindicators of historic and current nutrient concentrations. They are ubiquitous, well preserved, 

and sensitive to even subtle environmental shifts (Dixit, et al., 1992) 

Although Lake Parker overlies phosphatic deposits, the paleolimnological record from the 

study indicates that the lake was naturally mesotrophic. Several lines of quantitative evidence 

(diatom transfer rates and nutrient accumulation rates) suggest progressive increases in total 

phosphorus and chlorophyll a in the lake between 1920 and 1980. Net accumulation rates of 

phosphorus have increased more than 10-fold in this century. In addition, there is no 

evidence of substantial macrophyte presence in the lake (Brenner, Whitmore, Flannery, and 

Binford, 1993). As a result of human disturbances that affected both the watershed and 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 31

surrounding airshed, the authors estimate that the lake underwent substantial cultural 

eutrophication during this time period. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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Chapter 4: ASSESSMENT OF SOURCES 

4.1 Overview of Modeling Process 

 Lake Hancock is the most downstream lake in the Saddle Creek drainage basin, which 

makes Lake Hancock the “primary basin” in the model (the term “primary basin” in the 

Watershed Assessment Model refers to a collection of sub-basins or basins that discharge to 

a single receiving waterbody).The primary basin setup procedure used to model Lake 

Hancock is described in detail in “The WAM Watershed Assessment Final Report of the Lake 

Hancock Basin” (see Appendix H). The WAM model was then linked to the BATHTUB 

model. The BATHTUB model simulates nutrients in reservoirs and lakes based on annual 

average inputs. This model is described in detail in “The BATHTUB Framework for the Lake 

Hancock Basin, Florida, Final Report” (see Appendix F). 

The external load assessment conducted by the Watershed Assessment Model (WAM) and 

BATHTUB models was intended to determine the loading characteristics of the various 

sources of pollutants in the Lake Hancock Basin, including the Lake Hancock and Lower 

Saddle Creek watersheds (see Figure 4.1). Assessing the external load entailed assessing 

land use patterns, soils, topography, hydrography, point sources, sewer service area 

coverages, climate, and rainfall to determine the volume, concentration, timing, location, and 

underlying nature of the point and nonpoint sources of nutrients to the lake. 

WAM is a tool that has been shown to be useful in the assessment of watershed-related 

properties. WAM was developed to allow engineers and planners to assess the water quality 

of both surface water and ground water. The model simulates the primary physical processes 

important for watershed hydrologic and pollutant transport. The model assesses the 

hydrology of the watershed using imbedded models including “Ground Water Loading Effects 

of Agricultural Management Systems” (GLEAMS; Knisel, 1993), “Everglades Agricultural Area 

Model” (EAAMod; Botcher et al., 1998; SWET, 1999), and two submodels written specifically 

for WAM to handle wetland and urban landscapes. Dynamic routing of flows is accomplished 

through the use of an algorithm that uses a Manning’s flow equation-based technique 

(Jacobson et al., 1998). 

BATHTUB is a U. S. Army Corps of Engineers steady-state model. The model incorporates 

several empirical equations of nutrient settling and algal growth to predict steady-state nutrient 

and chlorophyll a concentrations based on waterbody characteristics, hydraulic 

characteristics, and nutrient loadings. BATHTUB is capable of predicting concentrations of 

chlorophyll a, total nitrogen (TN), total phosphorus (TP), and transparency in a waterbody 

under different loading conditions (QEA, LLC, 2005).
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 33

Figure 4.1 Aerial View of the Lake Hancock and Saddle Creek Watershed, Polk 

 County, Florida, 2004 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 34

4.2 Potential Sources of Nutrients in the Lake Hancock and Lower Saddle 

 Creek Watersheds 

An important part of the TMDL analysis is the identification of pollutant source categories, 

source subcategories, or individual sources of the pollutant of concern in the watershed and 

the amount of pollutant loading contributed by each of these sources. Sources are broadly 

classified as either “point sources” or “nonpoint sources.” Historically, the term point sources 

has meant discharges to surface waters that typically have a continuous flow via a 

discernable, confined, and discrete conveyance, such as a pipe. Domestic and industrial 

wastewater treatment facilities (WWTFs) are examples of traditional point sources. In 

contrast, the term “nonpoint sources” was used to describe intermittent, rainfall driven, diffuse 

sources of pollution associated with everyday human activities, including runoff from urban 

land uses, agriculture, silviculture, and mining; discharges from failing septic systems; and 

atmospheric deposition. 

However, the 1987 amendments to the Clean Water Act redefined certain nonpoint sources of 

pollution as point sources subject to regulation under the EPA’s National Pollutant Discharge 

Elimination Program (NPDES). These nonpoint sources included certain urban stormwater 

discharges, including those from local government master drainage systems, construction sites 

over five acres, and a wide variety of industries (see Appendix A for background information 

on the federal and state stormwater programs). 

To be consistent with Clean Water Act definitions, the term “point source” will be used to 

describe traditional point sources (such as domestic and industrial wastewater discharges) 

and stormwater systems requiring an NPDES stormwater permit when allocating pollutant 

load reductions required by a TMDL (see Section 6.1). However, the methodologies used to 

estimate nonpoint source loads do not distinguish between NPDES stormwater discharges 

and non-NPDES stormwater discharges, and as such, this source assessment section does 

not make any distinction between the two types of stormwater. 

4.2.1 Point Sources

Lake Lena Sub-basin 

There are two active National Pollutant Discharge Elimination System (NPDES) permitted 

facilities that are authorized to discharge to surface waters within the Lake Lena sub-basin: 

the City of Auburndale Allred Domestic Wastewater Treatment Facility (WWTF) (NPDES 

FL0021466) and the Florida Distillers Company – Auburndale (NPDES FL0003051). The 

Auburndale WWTF is a complete mix extended oxidation ditch domestic wastewater treatment 

facility, with a 1.4 million gallon a day (MGD) annual average daily flow. The facility is 

operated to achieve secondary treatment with basic disinfection for land application of effluent 

and/or advanced secondary treatment with basic disinfection and de-chlorination prior to 

discharging to Lake Lena Run, the outflow tributary from Lake Lena. Effluent disposal to Lake 

Lena Run is authorized up to a 0.65 MGD monthly average daily flow. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 35

The Florida Distillers facility is a citrus and cane molasses fermentation and bottling plant 

with a 2.6 MGD design capacity. The facility is involved in the manufacture of brandy, rum, 

and grain whiskey from cane, citrus, and grains. The materials are mashed with water, 

pasteurized, fermented, concentrated, and subsequently distilled, blended, and bottled. The 

liquid waste stream is evaporation condensate, cleaning water, cooling water, and sanitary 

wastewater. The wastewater undergoes neutralization, flow equalization and biological 

treatment through an activated sludge plant. The effluent is chlorinated, aerated and 

discharged through Outfall D002. Effluent disposal consists of a 0.5 MGD monthly average 

daily flow permitted surface water discharge to Lake Lena Run, the outflow tributary from 

Lake Lena. 

The discharges from the Auburndale WWTP and Florida Distillers facility were considered 

significant enough, in terms of volumes and concentrations, to affect modeling results and 

as a result, were incorporated into the WAM model and in determining TMDL point source 

loads (see Figure 4.2).

Lake Parker Sub-basin 

Two active permitted fossil fuel power generation facilities are located on the banks of Lake 

Parker: the Lakeland Larson Memorial Plant (NPDES FL0026298) and the Lakeland 

Electric McIntosh Plant (NPDES FL0026301). The Larsen facility has a design capacity of 

115 MGD for unit #001 and 115 MGD for unit #002. The McIntosh facility has a design 

capacity of 115.2 MGD for unit #1, while Unit #2 ceased operations in 1988. The plants 

withdraw water from Lake Parker to use as once through cooling water and cooling tower 

make-up water and return the water to the lake. In essence, water is removed from the 

lake, used for cooling, and then returned to the lake with an insignificant volumetric loss or 

nutrient contribution. The Larsen and McIntosh facility discharges were not considered 

significant enough, in terms of volumes and concentrations, to affect modeling results and 

as a result, were not incorporated into the WAM model and in determining TMDL point 

source loads (see Figure 4.2). 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 36

Figure 4.2 Lake Hancock and Lower Saddle Creek Watershed Lake Control 

 Structures and Active NPDES Facilities 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 37

 Municipal Separate Storm Sewer System Permittees 

Municipal separate storm sewer systems (MS4s) may discharge nutrients to waterbodies in 

response to storm events. To address stormwater discharges, the EPA developed the 

National Pollutant Discharge Elimination System (NPDES) stormwater permitting program in 

two phases. Phase I, promulgated in 1990, addresses large and medium MS4s located in 

incorporated places and counties with populations of 100,000 or more. Phase II permitting 

began in 2003. Regulated Phase II MS4s, which are defined in Section 62-624.800, F.A.C., 

typically cover urbanized areas serving jurisdictions with a population of at least 10,000 or 

discharges into Class I or Class II waters, or Outstanding Florida Waters. 

The stormwater collection systems in the Lake Hancock Basin, which are owned and operated 

by Polk County in conjunction with the Florida Department of Transportation (FDOT), are 

covered by a NPDES Phase I MS4 permit (Figure 4.3). The Lake Hancock and Lower Saddle 

Creek watersheds are situated between the cities of Lakeland, Winter Haven, Auburndale, 

and Bartow. The City of Lakeland has areas in it’s jurisdiction located within the Lake 

Hancock Basin. At this time, it is unknown if local governments located in the lake and creek 

watersheds have applied for coverage under the Phase II NPDES MS4 permit. 

As a note, numerous Polk County stormwater Capital Improvement Projects (CIPs) are 

currently under construction or are anticipated in the near future that are designed to reduce 

nutrient and sediment loadings to lakes and watersheds that contribute water quantity and 

quality to Lake Hancock. Current and future projects address stormwater discharges from 

lakes Gibson, Hollingsworth, John, Mirror, Morton, and Parker. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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Figure 4.3 Phase I MS4 Coverage Areas for the Lake Hancock Basin 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 39

4.2.2 Nonpoint Sources and Land Uses 

Unlike traditional point source effluent loads, nonpoint source loads enter at so many locations 

and exhibit such large temporal variation that a direct monitoring approach is often infeasible. 

For the Lake Hancock and Lower Saddle Creek TMDLs, all nonpoint sources were evaluated 

by use of a watershed and lake modeling approach. Table 4.1 shows the existing area of the 

various land use categories examined and modeled for the Lake Hancock Basin. Figure 4.4

shows the drainage basin area for the lake and creek, and the spatial distribution of the 

existing land uses shown in Table 4.1. Figure 4.5 shows the spatial distribution of land use 

coverages for the Lake Hancock Basin when converted to “natural background” land cover. 

The predominant existing land coverages for the Lake Hancock Basin (which includes all nine 

sub-basins) are low, medium, and high density residential (20.2%); followed by extractive-post 

phosphorus mining (16.2%); agriculture (14.2%); and commercial, industrial, transportation, 

and utilities (8.1%). These coverages account for 58.6 percent of the land use in the Lake 

Hancock Basin. Lakes and interconnected waterways/streams/wetlands etc. account for 23.2 

percent of the watershed. The areas occupied by anthropogenic land uses account for 63.5 

percent of the watershed. 

Land use coverages for the Lake Hancock Basin were aggregated using the Florida Land 

Use, Cover and Forms Classification System (FLUCCS, 1999). The spatial distribution and 

acreage of different land use categories for WAM were identified using the 1999 land use 

coverage (scale 1:24,000) provided by the Southwest Florida Water Management District 

(SWFWMD) contained in the Lake Hancock Basin WAM model developed by Soil and Water 

Engineering Technology, Inc., (2005).
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 40

Table 4.1 Lake Hancock Basin Existing Land Use Descriptions 

FLUCCS ID Lake Hancock Basin Existing Land Use Coverage Acres Sq Miles Percent

1600 Extractive-Phosphorus Mining 16,210.0 25.33 16.15% 

1200 Medium Density Residential, Fixed Single Family Units 13,155.8 20.56 13.11% 

5201 Interconnected Lakes 12,179.8 19.03 12.13% 

2100 Pastures and Fields 8,942.7 13.97 8.91% 

6150 Stream and Lake Swamps (Bottomland) 6,138.1 9.59 6.11% 

1800 Recreation 4,989.0 7.80 4.97% 

2210 Citrus Groves 4,875.4 7.62 4.86% 

1100 Low Density Residential, Fixed Single Family Units 4,304.6 6.73 4.29% 

1400 Commercial and Services 3,679.4 5.75 3.67% 

4340 Hardwood - Conifer Mixed 2,908.4 4.54 2.90% 

1300 High Density Residential, Fixed Single Family Units 2,834.3 4.43 2.82% 

5300 Reservoirs 2,619.3 4.09 2.61% 

1900 Undeveloped Land 2,043.6 3.19 2.04% 

1500 Industrial 1,991.7 3.11 1.98% 

6410 Freshwater Marshes 1,692.7 2.64 1.69% 

8100 Transportation 1,556.8 2.43 1.55% 

6210 Cypress 1,349.2 2.11 1.34% 

2600 Old Field 1,346.7 2.10 1.34% 

1700 Educational Facilities 1,238.0 1.93 1.23% 

4110 Pine Flatwoods 1,215.8 1.90 1.21% 

8300 Utilities 859.9 1.34 0.86% 

7400 Barren Land 761.1 1.19 0.76% 

3200 Prairies 600.5 0.94 0.60% 

6300 Wetland Forested Mixed 575.8 0.90 0.57% 

4200 Upland Hardwood Forest 437.4 0.68 0.44% 

6440 Emergent Aquatic Vegetation 378.1 0.59 0.38% 

5200 Lakes 355.8 0.56 0.35% 

6430 Wet Prairies 274.3 0.43 0.27% 

2410 Tree Nurseries 165.6 0.26 0.16% 

3100 Herbaceous 135.9 0.21 0.14% 

2140 Row Crops 126.0 0.20 0.13% 

6200 Wetland Coniferous Forest 98.8 0.15 0.10% 

4100 Upland Coniferous Forests 93.9 0.15 0.09% 

3290 Other Shrubs and Brush 66.7 0.10 0.07% 

2520 Dairies 61.8 0.10 0.06% 

2550 Tropical Fish Farms 29.7 0.05 0.03% 

6530 Inland Shores/Ephemeral Ponds 29.7 0.05 0.03% 

8200 Communications 22.2 0.03 0.02% 

2310 Cattle Feeding Operation 19.8 0.03 0.02% 

6100 Mixed Wetland Hardwoods 12.4 0.02 0.01% 

4400 Coniferous Plantations 7.4 0.01 0.01% 

Total 100,383.5 156.85 100 
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Figure 4.4 Lake Hancock and Saddle Creek Existing Land Use Coverage
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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Figure 4.5 Lake Hancock and Saddle Creek Natural Background Land Use Coverage 

 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 43

Polk County Population 

According to the U.S Census Bureau, the population density in Polk County, in the year 2000, 

was at or less than 258.2 people per square mile. The Census Bureau reports that the total 

population in 2000 for Polk County, which includes (but is not exclusive to) the Lake Hancock 

and Lower Saddle Creek watersheds, was 483,924, with 226,376 housing units. Polk County 

occupies an area of approximately 2,009 square miles. For all of Polk County, the Census 

Bureau reported a housing density of 120.8 houses per square mile. Polk County is just 

below the average housing density for Florida counties of 134.3 housing units per square mile 

(U.S. Census Bureau Web site, 2004). 

Polk County Septic Tanks 

Onsite sewage treatment and disposal systems (OSTDSs), including septic tanks, are 

commonly used where providing central sewer is not cost-effective or practical. When 

properly sited, designed, constructed, maintained, and operated, OSTDSs are a safe means 

of disposing of domestic waste. The effluent from a well-functioning OSTDS is comparable to 

secondarily treated wastewater from a sewage treatment plant. When not functioning 

properly, however, OSTDSs can be a source of nutrients (nitrogen and phosphorus), 

pathogens, and other pollutants to both ground water and surface water. 

As of 2001, Polk County had a cumulative registry of 112,848 septic systems. Data for septic 

tanks are based on 1970 – 2001 census results, with year-by-year additions based on new 

septic tank construction. The data do not reflect septic tanks that have been removed going 

back to 1970. From fiscal years 1993–2004, 1,151 permits for repairs were issued in Polk 

County (Florida Department of Health, 2004). Based on the number of permitted septic tanks 

and housing units (226, 376) located in the county, approximately 50 percent of the housing 

units are connected to a central sewer line (i.e., wastewater treatment facility), with the 

remaining 50 percent utilizing septic tank systems. 

4.3 Estimating Point and Nonpoint Source Loadings 

Model Approach 

WAM was utilized to estimate the nutrient loads within and discharged from the Lake Hancock 

Basin. WAM is a Geographic Information System (GIS) based model that allows users to 

interactively simulate and assess the environmental effects of various land use changes and 

associated land use practices. 

WAM utilizes ESRITM ArcView 3.2 with Spatial Analyst 2.0 to analyze and display model input 

and output using grids. Grid datasets, as opposed to polygon datasets, spatially represent 

geographic data as a collection of raster cells. Each cell contains attributes of the dataset, 

(e.g., land use code numbers) that can be overlaid with cells of other grids. The benefits of 

using grids over polygons include computational speed and output resolution. Output can be 

displayed by grid cell, as opposed to by sub-basin polygon. The cell size is dependant on the 

desired resolution. A grid cell size of one hectare was chosen, with the intent that this would 

adequately characterize the land use and capture linear features such as highways (SWET, 

2005). 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 44

The WAM model water quality parameters (impact parameters) simulated for Lake Hancock

and the Saddle Creek watershed included: Water quantity, soluble nitrogen (N) forms 

(ammonia, soluble organic, nitrate), particulate N, ground water N, soluble phosphorus (P), 

particulate P, ground water P, sediment, 5-day biochemical oxygen demand (BOD5), and land 

sourced dissolved oxygen. GIS datasets of land use, soils and rainfall are used to calculate 

the combined impact of the watershed characteristics for a given grid cell. Once the 

combined impact for each unique cell within a watershed is determined, the cumulative impact 

for the entire watershed is determined by attenuating the constituent to the sub-basin outlets. 

Constituents are attenuated based upon the flow distances (overland to nearest water body, 

through wetlands or depressions and within streams to the sub-basin outlet), flow rates in 

each related flow path and the type of wetland or depression encountered. Figure 4.6 shows 

the conceptual routing schemes and flow distances that are calculated for each cell (SWET, 

2005). 

Figure 4.6 WAM Conceptual Routing Diagram (SWET, 2005)

A portion of the flow in each cell is converted to ground water based on the soil type and the 

amount of imperviousness estimated for each land use. Surface flow that enters depressions 

is also converted to ground water. Ground water is routed to the nearest stream unless 

directed otherwise. 

The hydrologic contaminant transport modeling is accomplished by first simulating all of the 

unique grid cell combinations of land use, soils, and rainfall by using one of several source cell 

models including GLEAMS (Knisel, 1993), EAAMOD (Bottcher et al., 1998; SWET, 1999), a 

wetland module, and an urban module. The time series outputs for each grid cell is then 

routed and attenuated to the nearest stream and then through the entire stream network of the 

watershed. Dynamic routing of flows is accomplished through the use of an algorithm, 

BLASROUTE.exe, that uses a non-linear reservoir technique (Jacobson et al., 1998). Figure 

4.7 shows a flow diagram of the hydrologic contaminant transport modeling component of the 

overall WAM model. 

Depression 

Overland 

Wetland 

Stream 

Flow Routing

Grid Cell

Basin Outlet 

GW

Wetland 

(1 ha) 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 45

Field Model 

Parameters Files 

Unique LU/Soil

Grid Cell 

Coverages

Cell

Loads

Cumulative

Loads

WAM

INTERFACE

(Algorithms

& SubModels

Executed)

WAM

Outputs and

Intermediate

files

Data Inputs

Databases

GIS Coverages

Attenuation

Coefficients

Distance

Coverage

Land Use Topography

Unique 

Parameter

Sets

Land Attenuation PreProcessing

Stream Reach 

Flow Rates & 

Concentrations

GIS Coverage

ASCII Datefile

Interface Operation

Stream Routing 

Network

River Outlet 

Stages

Hydrography Subbasins

Land Use

(LU)

Soils

Rainfall 

Zone (new)

Land Use

Soils

Default Values

BUCSHELL BLASROUTE

Create/Link Model

Parameter Sets 

for Cells

Simulate Unique

Cells for Load

Estimates

Overlay 

Coverages

Attenuate to

Streams

Stream 

Routing

Fortran SubModel

LEGEND

Edit Land Use

& Display 

I/O Files

 Generate Attenuation Distances

Climatic Data

Sewage Serv. 

Area

Figure 4.7 WAM Dynamic Modeling Approach (SWET, 2005)

While BATHTUB has the capability to simulate large, sinuous reservoirs and lakes using 

multiple model cells, the size and nature of the eleven lakes evaluated supported the 

designation of one BATHTUB segment for each lake. However, because of the 

interconnectedness of the eleven lakes, including Lake Hancock, all eleven lakes were 

incorporated into a single BATHTUB model framework containing eleven linked segments. 

The outflow from each lake enters the next lake downstream. Surface water and ground 

water inputs are designated as tributaries in the model (one set to each lake). These inputs 

are provided by WAM which was explicitly set up to output the incremental surface water and 

ground water quantity and quality flowing into each of the BATHTUB-simulated lakes. That is, 

the tributaries designated in the BATHTUB model have flows and concentrations that reflect 

their local upstream (between lakes) sources only. Ground water seepage from each lake is 

simulated using BATHTUB’s channels. A schematic of the model framework is shown in 

Figure 4.8. All flows that do not point to a lake represent flows that are lost to the system. 

Daily WAM results were computed for the time period 1994 to 2003. The WAM results were 

averaged on an annual basis to develop eleven separate BATHTUB model scenarios, one for 

each year (QEA, LLC, 2005).
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 46

Figure 4.8 Model Schematic Depicting the Interconnected Eleven Lakes Modeled for 

the Lake Hancock Watershed (QEA, 2005) 

Land Use and Soils 

All of the GIS spatial datasets necessary to set up WAM were provided by the Department in 

custom Albers projection in the HPGN (metric) datum. Most of the datasets are from other 

sources including Southwest Florida Water Management District (land use), Natural Resource 

Conservation Service (soils), and United States Geographical Survey (topography and 

hydrography). The SURGO soils datasets were modified to include abbreviated soil 

designations so that these attributes would match WAM soils database established for the 

State. The land use dataset utilizes the Florida Land Use Cover Classification System 

(FLUCCS), which is also utilized by WAM (as noted in Chapter 4, Section 4.2.2). 

Hydrologic Data 

National Hydrologic Datasets (NHDs) were reviewed but were not used because of the lack of 

information and ability to define the hydrologic stream network within the Lake Hancock Basin. 

Instead, a detailed water management modeling assessment performed by Keith and 

Schnars, P. A., (2003) for the Polk County Board of County Commissioners and SWFWMD 

was utilized. 

Banana

SW

GW GW

Lena

SW

GW GW

Hancock

SW

GW

Out of Model 

Domain

Bentley

SW

GW GW

Hollings -

worth

SW

GW

GW

Eagle

SW

GW GW

Spirit

SW

GW GW

Gibson

SW

GW GW

Crago

SW

GW GW

Parker

SW

GW GW

Bonny

SW

GW GW

SW=Surface Water 

GW=Ground Water 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 47

The Primary Basin Setup procedure available in WAM was utilized to layout and code the 

stream network. The line segments of the Keith and Schnars reach coverage were coded 

with numbers in descending order from upstream to downstream. Not all of the segments 

were utilized. For modeling purposes, it is possible to represent clusters of segments as one 

reach. Line segments were added along the boundaries of the lakes to form shorelines. 

These shorelines were needed to properly calculate overland distances to the lakes (used for 

attenuation). In total, 98 hydrologic model reaches were assigned. A profile of these reaches 

is shown in Figure 4.9 (SWET, 2005). 

 Figure 4.9 Model Reaches and Estimated Depressions 

 Attenuation Distances 

Depressions 

Depressions are one of the three geographic features (wetlands, streams and depressions) 

that WAM routes runoff to and attenuates. Areas that drain to depressions are attenuated 

differently than areas that drain via surface water to the streams. Runoff entering depressions 

converts to ground water with very little phosphorus re-emerging in the streams. A grid of 

topographical and potential isolated depressional areas were created by an algorithm in the 

WAM Primary Basin Setup. This algorithm utilizes wetlands from the land use dataset, 

depressional soils such as surrency of the soils dataset, hydrography and topography. A grid 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 48

of topographical depressed areas is produced based on the topography grid, which was 

created from the USGS DEMs. Grid functions available in ArcViewTM Spatial Analyst were 

then used to locate depressions and determine their minimum elevation and depth at which 

runoff overflow would occur. The depth is added to the minimum elevation to determine the 

overflow elevation. All elevations equal to or less than this elevation in the region of the sink 

are identified and converted to a new grid of topographic depressions. A wetland and 

depressional soil grid was then created by selecting and merging those features from their 

respective source grids. These areas represent potentially depressional areas as opposed to 

topographic depressions. Both grids are then converted to polygon shapefiles. Potential 

depressions that lie in areas where land slopes are sufficient to generate runoff discharge are 

removed. The topography grid is then used to create a grid of slope values. Polygons of 

potential depressional areas that lie over an area with an average slope that is above a set 

minimum slope are then removed. 

The hydrography dataset is used in the algorithm to eliminate areas that are on or near 

“connected” hydrologic features. Connected features represent those line segments of the 

hydrography that form a contiguous drainage network including boundaries of lakes and 

wetlands. Any such boundaries that are isolated away from the connected system are not 

utilized in the analysis. Polygons that are within a set distance from the connected system are 

removed in both the topographic and potential depression shapefiles. This is based on the 

assumption that if the depression is close enough to the stream network, it is most likely 

connected to the network. 

A new screening process, however, was added specifically for the Lake Hancock watershed 

study when it was discovered that several small topographic depressions were appearing in 

heavily urbanized areas. Considering the nature of urban drainage, it is likely that drainage 

from these areas is captured and conveyed by local culverts. The algorithm was modified to 

exclude depressions in areas dominated with urban land use. Figure 4.9 shows the results of 

the analysis for depressions and stream reaches (SWET, 2005).

WAM attenuates water quality parameters in the runoff based on distances and the type of 

geographic feature the runoff passes through (upland, wetland, depression and stream). The 

WAM Primary Basin Setup includes an algorithm to develop a series of grids for this purpose. 

ArcViewTM Spatial Analyst cost distance functions are used to both determine distance and 

attributes of the feature that is found. For example, when the closest wetland is found, the 

wetland FLUCCS number can also be returned. In addition, a grid of wetland distances to 

streams can be accessed to return the distance to the next feature (SWET, 2005). 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 49

Rainfall 

Rainfall datasets were created from monitoring 

information obtained from the National Weather 

Service (NWS). The stations were initially chosen 

based on their locations for adequate spatial 

coverage of the study area and for the appropriate 

period of record. For flexibility in modeling, it is 

important to have an adequate period of record. A 

13-year period between January 1992 and 

December 2004 was chosen, though it was 

expected that the model would not utilize this 

entire period. The model uses the first two years 

of data to reach equilibrium with antecedent 

conditions. The model output reflects any 

remaining years of input data. Only years 1994 to 

2003 were used for generating files for the 

BATHTUB model. 

The rainfall records were then reviewed for 

completeness. Some stations were rejected because of abnormal annual rainfall compared to 

surrounding stations. The three USGS stations shown were first considered, but upon data 

review the Winter Haven station appeared to be quite different from the other two stations. 

When it was found that this station’s data had not been verified after 1999, it was decided to 

use only the Bartow (COOP: 080478) and Lakeland (COOP: 084797 and COOP: 084802) 

National Weather Service stations. These data were retrieved from the Climate Interactive 

Rapid Retrieval User System (CIRRUS) hosted by the Southeast Regional Climate Center, 

2005. The data from the selected rainfall stations was formatted and converted to centimeters 

for use by WAM. Theissen’s polygon method was applied to create rainfall zones for the 

stations noted above and shown in Figure 4.10. 

Control Structures 

Six major water control structures located within the Lake Hancock and Saddle Creek 

watershed were incorporated into the WAM model. These structures are located at lakes 

Arietta (P-3), Banana, Gibson, Hancock/Lower Saddle Creek (P-11), Lena (P-1), and Parker. 

Most of the structures in this basin consist of weirs that are operated to maintain optimum lake 

elevations. The major control structures (Figure 4.2) are operated and maintained by the 

Southwest Florida Water Management District. Several other smaller structures were added 

to the model to simulate culvert connections and other water control features. The elevation 

controls were adjusted to reflect observed water levels throughout the basin (SWET, 2005). 

Ground Water 

An option in WAM allows ground water to be routed to specified locations as opposed to the 

closest downstream waterbody, which is how surface water is routed. This option is 

particularly useful for dealing with springsheds or with deep surficial systems where ground 

water emerges further downstream as opposed to the nearest stream. It is also possible to 

send ground water out of the system to an offsite spring or as recharge to underlying aquifer 

Figure 4.10 Rainfall Stations and Zones
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 50

system by designating the ground water zone as discharging to reach number 1, which by 

default is an offsite reach. In the Lake Hancock Basin, it was assumed that some ground 

water discharges to nearby streams/lakes, while the majority percolates to the deeper Upper 

Floridian Aquifer (UFA). To reflect this, buffers were created around the streams and lakes 

(200 meters for streams and 500 meters for lakes) that included ground water zones equal to 

the nearest reach number. Reach number 1 was assigned to any areas outside of these 

buffers. Figure 4.11 shows the zones of surface water (Stream Node) and ground water (GW 

Node) distribution. Areas shaded in gray discharge to the UFA (SWET, 2005).

 Stream Node GW Node

Figure 4.11 Surface Water and Ground Water Distribution Zones 

Several previous studies in the Lake Hancock Basin found that significant leakage to the UFA 

is occurring from most of its lakes and streams. For example, Environmental Research and 

Design (1999) estimated by in-situ leakage studies and USGS data that Lake Hancock 

receives about 4-6 inches of ground water inflow per year, but leaks between 25 to 35 inches 

to the UFA per year. To better handle this leakage component in the basin, WAM was 

modified so that leakage rates for each stream and lake reach could be assigned. These 

leakage rates are the primary calibration factors for this basin. This leakage rate is calculated 

by the following equation: 

Reach leakage rate (m3

/y) = Area x Kleak x Relative Head 

Where, Area = reach’s water surface area (m2

) 

 Kleak = leakage coefficient (m/y) 

 Relative Head = (water surface elevation – impeding layer elevation)/ 

 unit thickness – dimensionless (SWET, 2005) 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 51

WAM Model Linkage to the BATHTUB Model 

GIS and model data set inputs for the WAM model included land use, soils, topography and 

depressions, hydrogaphy, USGS gage and flow volume, septic tanks, water use pumpage, 

point sources, rainfall, ground water, atmospheric deposition, solar radiation, control 

structures, and attenuation distances/stream reaches. 

The BATHTUB model simulates lake water quality based on annual average inputs. The 

inputs required for BATHTUB are the following annual data: rain (amount and TN and TP 

concentrations), evaporation, surface water inflow volumes and TN and TP loads, ground 

water inflow volumes and TN and TP loads, and leakage volume. Because BATHTUB is 

unable to vary the rainfall rate between lakes, it was decided that WAM would include rain 

inputs as part of its surface reach loads, so that the rain zones could be represented. 

Therefore, BATHTUB inputs show no rainfall. BATHTUB has been set up to simulate Lake 

Hancock and its ten major contributing lakes. The flow routing to and between lakes is built 

into both WAM and BATHTUB. BATHTUB routes flow and constituents between lakes, but 

requires WAM to provide all flow and constituents generated above and between the lakes. 

Using the BATHTUB input decks, WAM produced a nonpoint source file for each lake reach 

that contained all of the inflow and constituent loads data needed by BATHTUB. These files 

and the normal WAM reach files were used by an Access database which processed and 

formatted the input data necessary for BATHTUB (SWET, 2005). 

WAM and BATHTUB Calibration 

The data used for calibration is included in the Department’s IWR database and the Polk 

County Water Atlas database. The WAM model was initially set up based on parameters 

presented in the modeling report just completed by BCI Engineers & Scientists, Inc. (2005). 

This report was extremely helpful, however, upon data review and discussion with local 

experts it was found that some of the structures, particularly their control elevations, had to be 

updated. Also, in the western basin near Lake John, the hydrography was verified to be quite 

different than what was shown in the report (i.e., Lake John was found to flow north and east 

through Summerset Lake instead of south). Also, a major culvert into the southeast end of 

Lake Crago from a series of old mining pits was also not represented. All of the flow and 

structure setting were verified against available lake stage data, which deemed the best 

hydrology data available to calibrate against because it was available throughout the basin. 

There were three flow stations located with the basin that were also used to verify net flow 

volumes. 

The parameters varied to obtain the best fit were the weir crest elevations for the lake 

structures and the leakage rates for each reach. The nearly closed lakes, such as Eagle, 

Spirit, Thomas, and Arietta, were the most difficult to calibrate because getting the leakage 

rates correct required numerous trial and error runs. Also, the balance of leakage between 

connected lakes like Parker, Crago, and Bonny required special attention so that significant 

backflow between the lakes was not generated, though some backflow is probably real. 

Another calibration issue was the 3-foot culvert from the upper end of Lake Crago to the 

connected mine pits located to the northeast. The reasonable leakage rates in these pits 

created the situation that there was a net positive flow from Lake Crago to these pits. WAM 

was able to handle this net negative reach inflow, but BATHTUB was not. Therefore, since 

the flows through this culvert were quite low compared to the other inflow to the lake, the 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 52

culvert was raised to prevent flow except during major events. This solved the BATHTUB 

problem and did not have a significant impact on the assimilative capacity for Lake Hancock. 

Water quality calibration was limited by the fact that only in-lake data were available and WAM 

currently does not have a lake sub-model to properly represent the nutrient dynamics, 

particularly internal loadings from bottom sediments, algal populations, and macrophytes. 

These limitations were the reason WAM was linked to BATHTUB, which is capable of 

handling the in-lake dynamics much better and on a long term basis. WAM performed fairly 

well in matching the general nutrient levels in several of the lakes, which gives confidence that 

the simulated nutrient loading rates to the lakes are reasonable (SWET, 2005). 

Lake Hancock Basin Existing Land Use Loadings 

The total loadings of nitrogen and phosphorus generated in the Lake Hancock Basin were 

estimated using the WAM and BATHTUB models. Modeling frameworks were designed to 

simulate the period 1994 through 2003. This time period had the best available seasonal data 

for the contributing sub-basins and also included the verified period for Group 3 waterbodies 

located in the Lake Hancock watershed. 

Based on the hydrology, and lake and stream interconnected reaches, nine major sub-basins 

were delineated in making up the Lake Hancock watershed. The nine sub-basins include 

Banana Lake and Banana Lake Canal, Cabbage Branch, Eagle Lake, K-Ville Branch, Lake 

Lena and Lake Lena Run/Creek, Lake Parker, Lower Saddle Creek, Middle Saddle Creek, 

and Upper Saddle Creek. Within the nine sub-basins making up the Lake Hancock 

watershed, eleven lakes were targeted and modeled based on nutrient impairment and the 

interconnected nature of the waterbodies contributing runoff and loadings to Lake Hancock 

and Lower Saddle Creek. The eleven lakes are Lake Gibson, Lake Crago, Lake Bonny, Lake 

Parker, Lake Lena, Lake Hollingsworth, Lake Bentley, Banana Lake, Spirit Lake, Eagle Lake, 

and Lake Hancock. All of these lakes are impaired for nutrients based on the Department’s 

Impaired Waters Rule methodology. Each lake was modeled separately to determine 

individual contributions to Lake Hancock and Lower Saddle Creek. Tables 4.2 through 4.7

illustrate the total water volume and loadings for TN and TP going into each of the eleven 

lakes from 1994 to 2003 based on the WAM and BATHTUB model results under current land 

use conditions. Loads were estimated based on lake surface rainfall, surface water inflow, 

ground water inflow, and septic inflow. Ground water loss/leakage from each lake was also 

calculated and subtracted from the total inflow volume. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 53

Table 4.2 Lakes Gibson and Crago Water Volume and Loadings for TN and TP 

 from 1994 to 2003 

Lake Gibson Lake Crago 

Year 

Water 

(hm3) TN (kg) TN (lbs) TP (kg) TP (lbs)

Water 

(hm3) TN (kg) TN (lbs) TP (kg) TP (lbs)

1994 6.7 10,815.4 23,843.9 836.9 1,845.1 1.8 1,532.0 3,377.6 206.5 455.2 

1995 7.0 13,422.2 29,590.9 864.3 1,905.5 1.3 975.5 2,150.7 124.9 275.4 

1996 5.5 8,323.0 18,349.1 714.1 1,574.4 1.4 1,050.1 2,315.0 173.4 382.3 

1997 8.4 16,079.5 35,449.3 1,182.1 2,606.2 1.4 1,249.8 2,755.3 153.9 339.2 

1998 6.9 12,176.4 26,844.4 870.4 1,918.8 1.3 986.6 2,175.0 122.8 270.7 

1999 4.7 8,676.8 19,129.0 642.2 1,415.8 1.2 1,117.2 2,463.1 156.0 343.8 

2000 3.7 8,950.2 19,731.8 516.1 1,137.9 0.9 1,025.8 2,261.4 118.7 261.8 

2001 4.7 10,787.6 23,782.6 710.6 1,566.6 0.9 806.1 1,777.1 96.4 212.5 

2002 8.3 12,066.5 26,602.1 1,061.1 2,339.3 1.8 1,479.6 3,262.1 197.8 436.0 

2003 6.9 13,944.7 30,742.9 829.8 1,829.4 1.0 713.7 1,573.3 78.7 173.4 

94-03 

Mean 6.3 11,524.2 25,406.6 822.8 1,813.9 1.3 1,093.6 2,411.1 142.9 315.0 

94-03 

Totals 62.7 115,242.4 254,066.1 8,227.7 18,138.9 12.9 10,936.4 24,110.6 1,429.0 3,150.3

hm3: Cubic Hectometers; kg: Kilograms; lbs: Pound 

Table 4.3 Lakes Bonny and Parker Water Volume and Loadings for TN and TP 

 from 1994 to 2003 

Lake Bonny Lake Parker 

Year 

Water 

(hm3) TN (kg) TN (lbs) TP (kg) TP (lbs)

Water 

(hm3) TN (kg) TN (lbs) TP (kg) TP (lbs)

1994 3.9 3,832.2 8,448.6 448.5 988.8 28.5 23,624.2 52,082.4 3,330.8 7,343.2 

1995 4.1 5,263.8 11,604.8 472.2 1,041.0 29.6 30,685.8 67,650.7 3,408.7 7,514.9 

1996 3.0 2,429.4 5,356.0 359.1 791.6 22.5 16,120.8 35,540.4 2,649.8 5,841.8 

1997 4.9 6,951.3 15,324.9 629.3 1,387.4 35.3 39,650.4 87,414.2 4,436.6 9,780.9 

1998 4.0 4,340.0 9,568.0 467.7 1,031.0 28.4 27,585.3 60,815.1 3,253.2 7,172.2 

1999 2.6 2,514.3 5,543.0 308.2 679.5 19.5 16,428.3 36,218.1 2,343.8 5,167.3 

2000 2.0 2,468.3 5,441.7 238.0 524.8 15.0 15,148.7 33,397.1 1,790.9 3,948.2 

2001 2.6 3,400.4 7,496.6 333.5 735.1 19.7 22,304.7 49,173.5 2,485.4 5,479.4 

2002 4.8 4,674.1 10,304.6 579.2 1,276.9 34.8 29,299.0 64,593.3 4,136.2 9,118.8 

2003 4.1 5,095.4 11,233.4 447.8 987.1 28.6 32,376.8 71,378.6 3,201.5 7,058.0 

94-03 

Mean 3.6 4,096.9 9,032.2 428.3 944.3 26.2 25,322.4 55,826.3 3,103.7 6,842.5 

94-03 

Totals 36.0 40,969.3 90,321.8 4,283.4 9,443.2 261.8 253,224.0 558,263.4 31,036.9 68,424.6

hm3: Cubic Hectometers; kg: Kilograms; lbs: Pounds 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 54

Table 4.4 Lakes Lena and Banana Water Volume and Loadings for TN and TP 

 from 1994 to 2003 

Lake Lena Banana Lake 

Year 

Water 

(hm3) TN (kg) TN (lbs) TP (kg) TP (lbs)

Water 

(hm3) TN (kg) TN (lbs) TP (kg) TP (lbs)

1994 3.1 4,862.6 10,720.3 380.5 838.8 11.8 19,178.6 42,281.6 1,846.3 4,070.4 

1995 4.7 9,690.2 21,363.2 637.0 1,404.4 13.1 21,642.2 47,713.0 2,048.2 4,515.4 

1996 1.9 1,550.2 3,417.7 229.3 505.4 9.0 13,498.4 29,759.0 1,459.6 3,217.9 

1997 4.6 10,021.9 22,094.6 732.4 1,614.6 16.8 29,160.4 64,287.7 3,015.3 6,647.7 

1998 5.6 9,849.3 21,714.1 794.6 1,751.8 14.4 17,896.8 39,455.8 2,342.6 5,164.6 

1999 1.4 1,861.0 4,102.8 163.6 360.7 7.5 12,011.8 26,481.5 1,261.5 2,781.2 

2000 1.1 2,326.6 5,129.2 126.9 279.8 5.8 12,030.6 26,522.8 1,003.4 2,212.1 

2001 1.4 2,823.9 6,225.6 204.5 450.9 8.4 16,435.4 36,234.0 1,553.9 3,425.7 

2002 2.8 3,903.2 8,605.1 374.8 826.3 15.5 25,754.7 56,779.4 2,566.8 5,658.7 

2003 6.1 11,516.0 25,388.3 887.8 1,957.3 14.5 19,000.5 41,889.0 2,247.6 4,955.2 

94-03 

Mean 3.3 5,840.5 12,876.1 453.1 999.0 11.7 18,661.0 41,140.4 1,934.5 4,264.9 

94-03 

Totals 32.7 58,404.9 128,760.8 4,531.4 9,990.0 116.8 186,609.6 411,403.7 19,345.2 42,649.0

hm3: Cubic Hectometers; kg: Kilograms; lbs: Pounds 

Table 4.5 Lakes Hancock and Hollingsworth Water Volume and Loadings for TN 

 and TP from 1994 to 2003 

Lake Hancock Lake Hollingsworth 

Year 

Water 

(hm3) TN (kg) TN (lbs) TP (kg) TP (lbs)

Water 

(hm3) TN (kg) TN (lbs) TP (kg) TP (lbs)

1994 84.3 95,809.9 211,224.8 12,901.6 28,443.2 4.9 12,135.9 26,755.1 560.5 1,235.6 

1995 92.7 104,720.5 230,869.2 15,015.7 33,104.0 5.2 16,619.0 36,638.7 578.3 1,274.9 

1996 67.0 70,727.9 155,928.3 11,013.8 24,281.4 3.9 3,107.1 6,850.0 438.6 966.9 

1997 127.8 134,996.1 297,615.5 23,884.2 52,655.7 6.3 21,147.9 46,623.1 703.9 1,551.9 

1998 108.4 109,122.0 240,572.9 19,501.5 42,993.5 5.2 14,557.2 32,093.2 525.4 1,158.4 

1999 56.5 62,991.0 138,871.5 9,798.8 21,602.7 3.4 8,036.1 17,716.6 387.7 854.7 

2000 45.9 59,478.1 131,126.9 8,443.0 18,613.5 2.6 9,500.9 20,946.0 290.4 640.2 

2001 66.7 78,445.6 172,943.0 12,962.3 28,576.9 3.4 11,431.4 25,201.9 393.6 867.7 

2002 115.5 116,668.0 257,208.9 19,492.5 42,973.6 6.1 13,817.9 30,463.3 685.9 1,512.2 

2003 106.6 109,343.0 241,060.2 18,321.6 40,392.2 5.2 15,868.4 34,983.8 532.0 1,172.9 

94-03 

Mean 87.1 94,230.2 207,742.1 15,133.5 33,363.7 4.6 12,622.2 27,827.2 509.6 1,123.5 

94-03 

Totals 871.4 942,302.2 2,077,421.2 151,335.0 333,636.7 46.3 126,221.9 278,271.6 5,096.3 11,235.4

hm3: Cubic Hectometers; kg: Kilograms; lbs: Pounds 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 55

Table 4.6 Lakes Bentley and Spirit Water Volume and Loadings for TN and TP 

 from 1994 to 2003 

Lake Bentley Spirit Lake 

Year 

Water 

(hm3) TN (kg) TN (lbs) TP (kg) TP (lbs)

Water 

(hm3) TN (kg) TN (lbs) TP (kg) TP (lbs)

1994 1.3 4,284.4 9,445.5 152.1 335.3 1.5 4,763.4 10,501.5 159.7 352.1 

1995 1.4 6,427.2 14,169.5 161.9 356.8 1.7 5,624.3 12,399.5 190.6 420.1 

1996 1.0 766.5 1,689.9 122.6 270.4 1.5 3,569.4 7,869.2 151.5 334.0 

1997 1.7 8,138.6 17,942.5 213.8 471.4 2.0 7,601.4 16,758.3 261.3 576.1 

1998 1.5 5,158.4 11,372.2 159.9 352.6 1.8 5,268.1 11,614.1 240.6 530.3 

1999 0.9 2,538.9 5,597.4 110.5 243.6 1.5 3,384.1 7,460.7 144.0 317.5 

2000 0.7 3,372.4 7,434.9 85.7 188.9 1.4 3,087.4 6,806.6 120.6 265.9 

2001 0.9 4,548.1 10,026.9 119.4 263.3 1.4 4,070.3 8,973.6 127.7 281.5 

2002 1.6 4,396.0 9,691.4 191.7 422.7 2.0 7,608.7 16,774.2 265.3 585.0 

2003 1.5 6,054.5 13,347.9 156.2 344.3 1.8 5,790.5 12,765.9 232.0 511.6 

94-03 

Mean 1.3 4,568.5 10,071.8 147.4 324.9 1.7 5,076.8 11,192.4 189.3 417.4 

94-03 

Totals 12.6 45,685.0 100,718.1 1,473.8 3,249.2 16.5 50,767.7 111,923.6 1,893.3 4,174.0

hm3: Cubic Hectometers; kg: Kilograms; lbs: Pounds 

Table 4.7 Eagle Lake Water Volume and Loadings for TN and TP 

 from 1994 to 2003 

Eagle Lake 

Year 

Water 

(hm3) TN (kg) TN (lbs) TP (kg) TP (lbs)

1994 5.7 21,801.6 48,064.3 624.6 1,377.1 

1995 5.9 22,129.8 48,788.0 647.2 1,426.9 

1996 4.6 15,462.0 34,087.9 560.3 1,235.2 

1997 7.2 28,597.2 63,046.1 811.8 1,789.6 

1998 5.9 19,421.4 42,816.8 649.4 1,431.8 

1999 4.0 15,395.9 33,942.2 510.2 1,124.8 

2000 3.5 17,420.4 38,405.5 489.6 1,079.5 

2001 4.1 21,855.3 48,182.8 543.6 1,198.4 

2002 7.1 25,974.2 57,263.3 753.4 1,661.0 

2003 5.8 19,534.5 43,066.1 613.5 1,352.6 

94-03 Mean 5.4 20,759.2 45,766.3 620.4 1,367.7 

94-03 Totals 53.7 207,592.3 457,662.9 6,203.7 13,676.9

hm3: Cubic Hectometers; kg: Kilograms; lbs: Pounds 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 56

Chapter 5: DETERMINATION OF ASSIMILATIVE 

CAPACITY

5.1 Determination of Loading Capacity for TN and TP 

Nutrient enrichment and the resulting problems related to eutrophication tend to be 

widespread and are frequently manifested far (in both time and space) from their source. 

Addressing eutrophication involves relating water quality and biological effects (such as 

photosynthesis, decomposition, and nutrient recycling), as acted upon by hydrodynamic 

factors (including flow, wind, tide, and salinity) to the timing and magnitude of constituent 

loads supplied from various categories of pollution sources. The assimilative capacity should 

be related to some specific hydro-meteorological condition such as an ‘average’ during a 

selected time span or to cover some range of expected variation in these conditions. Lake 

Hancock was modeled as part of an eleven lake series over a ten-year period of record 

(1994 – 2003). 

As discussed in Chapter 4, the WAM model was selected as the watershed model. It was run 

dynamically through the ten-year period of record with all the lakes linked together in their 

current configuration. BATHTUB was selected as the lake model. It was set up with all the 

lakes linked together and the model calibrated based on the annual average output from WAM 

and run year-by-year (1994 – 2003) for all eleven lakes. 

5.1.1 Rainfall 

The long-term average for the two rainfall gages used in the model [Bartow (COOP: 080478) 

and Lakeland (COOP: 084797 and COOP: 084802) National Weather Service stations] was 

52.01 inches/year. The 10-year average rainfall for the study period (1994 – 2003) was 55.23 

inches for Lakeland (60th percentile of the Lakeland long-term record) and 55.19 inches for 

Bartow (71st percentile of the Bartow long-term record) (see Table 5.1). Therefore, the study 

period represented a wetter than average period. However, it contained a very dry year, the 

year 2000, that was the driest year with 38.3 inches of rain recorded in Lakeland (10th

percentile of the long-term record) and with 35.9 inches recorded at Bartow (~ the 1st 

percentile of the long-term record). For the year 2000, evaporation exceeded rainfall. This 

created a year with very high in-lake concentrations in both the current condition and natural 

land use background scenario. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 57

Table 5.1 Bartow and Lakeland, Florida, Rainfall Stations 

 Used for Model Loading and Calibration 

Note: Lakeland stations missing data from September and October 1995. 

5.1.2 Model Calibration 

Watershed Assessment Model (WAM) 

WAM was calibrated by consultants for conditions in the years 1994 – 2003. Calibration 

consisted of a water balance approach to match the measured in-lake stages and flows at 

flow measuring points. An Access database tool was created to aggregate the daily 

predictions for surface water and ground water (flows and TN, TP concentrations) up to 

annual average conditions in a format compatible with the requirements of the BATHTUB 

model. For details on the WAM model see “WAM Watershed Assessment Model, Model 

Documentation and Users Manual,” Soil and Water Engineering Technology, Inc., 2005 

(Appendix J). For details on model calibration see the WAM Final Report, September, 2005 

(Appendix H). 

BATHTUB Model 

The consultant provided the Department with copies of ten BATHTUB input decks (one for 

each year 1994 – 2003) set up for current conditions, but not calibrated. The Department 

calibrated the BATHTUB model, which consisted of running each model year through all of the 

model options in BATHTUB to determine which set of models provided the best un-calibrated 

fit to the measured data. As a result of running through these models, it became apparent 

that for many of the lake/year combinations the watershed model was not delivering enough 

mass to match the measured data for either TN or TP. However, in other lake/year 

combinations, there was too much mass. Once a set of models was selected, the primary 

calibration for TN and TP was achieved by invoking BATHTUB’s internal loading rate 

functions for both TN and TP to match the measured in-lake mass. This Internal Loading (IL) 

rate integrates all of the missing mass. It is not proposed that the IL rate represents only 

those in-lake processes that either recycle mass within the lake or fix nitrogen from the 

atmosphere; it also includes all other missing mass. As such, it will be referred to as the 

Rainfall from Bartow and Lakeland 

Bartow 1900-2004 average = 53.7” 

Lakeland 1949-2004 average = 50.33” 

Year Lakeland Bartow 

1994 67.13 60 

1995 48.47 60.31 

1996 52.85 46.1 

1997 58.14 60.2 

1998 54.41 62.33 

1999 48.66 42.29 

2000 38.26 35.87 

2001 57.67 49.56 

2002 66.58 71.44 

2003 60.13 63.83 

94-03 Average 55.23” 55.19” 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 58

‘missing mass.’ Chlorophyll a was calibrated using the BATHTUB calibration coefficient. 

Each lake/year combination was calibrated individually, but once the chlorophyll a calibration 

was set, it remained unchanged for all other BATHTUB simulations (background and TMDL 

development). 

The phosphorous model that best fit Lake Hancock was Model 1, Second-Order, Available P 

model. The nitrogen model selected was Model 1, Second-Order, Available N model. The 

chlorophyll a model selected was Model 1, for P, N, Light and Flushing. Details regarding the 

selected models can be found in the BATHTUB Users Manual (U.S. Army Corps of Engineers, 

1999; Walker, W.W., 2004). Figures 5.1 – 5.4 illustrate the measured, un-calibrated, and 

calibrated data for TN, TP, chlorophyll a, and TSI for the ten-year modeled period (1994 – 

2003) for Lake Hancock. 

Lake Hancock Total Nitrogen

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Year

TN (ug/L)

TN-M easured TN-Uncalibrated TN-Calibrated

Figure 5.1 Lake Hancock Total Nitrogen Measured, Un-Calibrated, 

 and Calibrated Data from 1994 to 2003 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 59

Lake Hancock Total Phosphorus

0

100

200

300

400

500

600

700

800

900

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Year

TP (ug/L)

TP-M easured TP-Uncalibrated TP-Calibrated

Figure 5.2 Lake Hancock Total Phosphorus Measured, Un-Calibrated, 

 and Calibrated Data from 1994 to 2003 

Lake Hancock Chlorophyll a 

0

20

40

60

80

100

120

140

160

180

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Year

Chla (ug/L)

Chla-M easured Chla-Uncalibrated Chla-Calibrated

Figure 5.3 Lake Hancock Chlorophyll a Measured, Un-Calibrated, 

 and Calibrated Data from 1994 to 2003 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 60

Lake Hancock TSI

30

40

50

60

70

80

90

100

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Year

TSI

TSI-M easured TSI-Uncalibrated TSI-Calibrated

Figure 5.4 Lake Hancock TSI Measured, Un-Calibrated, and Calibrated 

 Data from 1994 to 2003 

5.1.3 Background Conditions 

WAM Model 

WAM was used to describe and evaluate the “natural land use background condition” for the 

entire Lake Hancock watershed, including Lower Saddle Creek. For this simulation, all 

current land uses were ‘reassigned’ to a mixture of Herbaceous, Prairies, Other Shrubs and 

Brush, Upland Coniferous Forest, Pine Flatwoods, Upland Hardwoods Forest, Hardwood 

Conifer Mix (the majority), Lakes, Interconnected Lakes, Reservoirs, Mixed Wetland 

Hardwoods, Streams and Lakes Swamps (bottomlands), Wetland Coniferous Forest, Cypress, 

Wetland Forested Mix, Freshwater Marshes, Wet Prairies, Emergent Aquatic Vegetation, 

Inland Shores and Ephemeral Ponds. The current condition was maintained for all waterbody 

physical characteristics. From this point forward, the natural land use background will be 

referred to as “background.” 

At first, the WAM was run with current rates of seepage around waterbodies and leakance 

from inside waterbodies. This resulted in such a large reduction in the total water flowing into 

the lakes that even with the significant reduction in external watershed loading, several 

lake/year combinations had higher concentrations of TN, TP, and chlorophyll a than under 

current conditions as the evaporation of 1.32 meters nearly exceeded inflow and the lakes 

dried up. To account for this water loss in the background condition, seepage around the 

lakes was adjusted back to background conditions in the model and leakance was adjusted 

down (50 percent of current rate) until the lake stages and surface areas approximated current 

conditions. Even under this scenario the total water inflowing to the lakes under the 

background scenario was less than current conditions, particularly in the drier years (1996 and 

2000). Again, this resulted in concentrations for some lake/year combinations being as great 

as they are under current conditions. In other words, the watershed model is indicating that 

under ‘natural land use’ dry conditions the lakes would have a trophic state similar to that of 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 61

today. Conversely, under average or wet conditions the natural land use trophic states were 

significantly less than current conditions. 

BATHTUB Model 

After achieving acceptable WAM background results, the BATHTUB model was run with no 

reduction in the total amount of missing mass (internal loading rate). As expected, with the 

reduction in total flow for the background condition and with no attenuation of the missing 

mass, many of the lake/year combinations did not improve. In fact, for the dry years the 

background condition was still worse than the current condition. In an effort to find the natural 

background, reductions in the missing mass were made. First, the BATHTUB model was 

used to identify the total external load of TN and TP under both the current condition and the 

background condition. Then the ratio of the change in external load between the background 

condition and the current condition (background/current) was applied to the missing mass 

(internal loading rate). This was called the attenuated case (A). This brought the in-lake 

trophic states down in the average and wet years, but many of the dry year lake trophic states 

remained higher in the background condition than in the current condition. As a result, the 

remaining missing mass was reduced until the worst case dry year trophic state was below 

the current conditions. This required an additional 75 percent reduction in the missing mass 

remaining after attenuation. The modeling abbreviations used in the tables, figures and report 

are explained below: 

Abbreviations Used

L 100 = leakance at current conditions (calibrated model) 

L50 = leakance reduced from current conditions by 50 percent 

L0 = leakance reduced to near zero (0.01 m) 

PC = results from calibrated BATHTUB model 

IL = missing mass (used internal loading rate to achieve mass balance in 

model calibration) 

ILA = missing mass changed by the ratio of the change in external mass of 

background/current condition. 

IL50 = ILA plus an additional 50 percent reduction in missing mass 

IL75 = ILA plus an additional 75 percent reduction in missing mass 

ILNIL = all missing mass eliminated (loading rate = 0.0) 

5.2 Selection of the TMDL Target 

It should be recognized that the direct application of natural background as the target TSI 

would not allow for any assimilative capacity. The IWR uses as one measure of impairment in 

lakes, a 10 unit change in TSI from “historical” levels. This 10 unit increase is assumed to 

represent the transition of a lake from one trophic state (say mesotrophic) to another nutrient 

enriched condition (eutrophic). The Department has assumed that allowing a 5 unit increase 

in TSI over the natural background condition would prevent a lake from becoming impaired 

(changing trophic states) and reserve 5 TSI units to allow for future changes in the basin and 

as part of the implicit margin of safety in establishing the assimilative capacity. 

 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 62

After examining the background runs for Lake Hancock, it was decided that the scenario with 

leakance set at 50 percent of the current condition and the attenuated missing mass reduced 

by an additional 75 percent represented the natural land use background condition. These 

conditions resulted in a background TSI of 69.4. As has been Department practice, when 

acceptable background conditions can be established, the target for TMDL development 

becomes the background TSI plus 5 TSI units (69.4 + 5 TSI units). Once the target TSI was 

established (a TSI of 74.4), the model was rerun with decreasing loads until the target TSI 

was met. 

In order to complete the TMDL for Lake Hancock and Lower Saddle Creek, load reductions 

had to be proposed for the ten upstream lakes contributing to Lake Hancock. Based on 

achieving the TMDL targets for each year of the ten-year period of record, a long-term annual 

average TSI was set at 74.3 for the TMDL. The 0.1 TSI difference between the target and the 

established TMDL may be considered as additional margin of safety (MOS). The range in TSI 

TMDL targets was between 66.2 and 83.1. In addition, water quality in Lower Saddle Creek is 

directly influenced by the water quality in Lake Hancock. As a result of this direct influence, it 

is anticipated that achieving the TMDL for Lake Hancock will result in achieving water quality 

standards in Lower Saddle Creek. 

The required annual average percent reduction for TN coming into Lake Hancock was 75.2 

percent, with an allowable long-term annual average loading of 318,497.6 kg/year (702,167.1 

lbs/year). The required annual average percent reduction for TP coming into the lake was 

75.5, with an allowable long-term annual average loading of 101,749.6 kg/year (224,319.5 

lbs/year). 

The annual percent reductions ranged between 64.3 and 81.6 for TN and between 64.9 and 

81.6 for TP. These reductions correspond to a range in loadings of 134,421.9 kg/year 

(296,349.6 lbs/year) to 476,505.4 kg/year (1,050,514.8 lbs/year) for TN, and between 

14,430.8 kg/year (31,814.5 lbs/year) to 166,848.9 kg/year (367,838.9 lbs/year) for TP. 

Maintaining the long-term annual average loadings for TN and TP established in this TMDL 

should result in attaining the target long-term annual average TSI of 74.3 (the model TMDL 

target is 74.4). 

Table 5.2 shows the TSI for the calibrated model (PC), the background model (IL75), the 

TMDL Target TSI, TMDL-TSI, and the percent reduction for Lake Hancock. The TSI for the 

calibrated model (PC), the background model (IL75), the TMDL Target TSI, TMDL-TSI, and 

the percent reduction for the ten lakes modeled for the Lake Hancock Basin are displayed in 

Appendix C.

Table 5.3 shows the mass for TN and TP for the calibrated model, TMDL, and percent 

reductions for Lake Hancock. The mass for TN and TP for the ten lakes modeled for the Lake 

Hancock Basin are displayed in Appendix D. 

Table 5.4 shows the annual average concentrations for TN, TP, and chlorophyll a for Lake 

Hancock. Annual average concentrations for the ten lakes modeled for the Lake Hancock 

Basin are displayed in Appendix E.

Figures 5.5 – 5.8 show the TMDL target, calibrated data, and L50-IL75 for TN, TP, chlorophyll 

a, and TSI for the ten-year modeled period (1994 – 2003) for Lake Hancock. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 63

Table 5.2 Lake Hancock TSI for PC, Background, TMDL Target, and 

 TSI-Unit Percent Reduction 

Lake Hancock 

TSI for Measured, PC, Background, TMDL Target, TMDL, and 

TSI-unit Percent Reduction Based on Background L50-IL75 

Year 

Color 

(PCU) Measured Calibrated

Background 

IL75 

Target 

IL75+5 TMDL 

Percent 

Reduction

1994 72.5 86.7 86.7 72.4 77.4 77.4 66.6 

1995 87.5 86.0 86.0 68.1 73.1 73.1 75.0 

1996 66.7 84.8 84.8 69.7 74.7 74.7 74.6 

1997 53.3 82.2 82.2 61.9 66.9 66.7 75.0 

1998 73.3 88.4 88.3 68.9 73.9 73.8 80.5 

1999 240.0 94.4 94.5 78.1 83.1 83.1 82.0 

2000 87.1 87.2 71.0 76.0 76.0 76.2 

2001 79.2 79.2 61.2 66.2 66.2 74.0 

2002 108.3 89.0 89.0 70.5 75.5 75.3 79.5 

2003 100.3 90.4 90.4 72.1 77.1 77.1 80.6 

Minimum 53.3 79.2 79.2 61.2 66.2 66.2 66.6 

Maximum 240.0 94.4 94.5 78.1 83.1 83.1 82.0 

Mean 100.2 86.8 86.8 69.4 74.4 74.3 76.4 

Table 5.3 Lake Hancock Mass for TN and TP for Calibrated Model, TMDL, 

 and Percent Reduction 

Lake Hancock 

Mass for TN and TP for Calibrated Model and TMDL, 

with Mass Percent Reductions (kg/year) 

Year 

TN-MASS 

Calibrated 

TN-MASS 

TMDL 

TN-MASS 

% Reduction 

TP-MASS 

Calibrated 

TP-MASS 

TMDL 

TP-MASS 

% Reduction 

1994 1,020,579.1 363,921.6 64.3 323,799.6 113,600.8 64.9 

1995 905,831.2 242,404.3 73.2 445,186.1 116,198.5 73.9 

1996 1,454,898.7 383,852.0 73.6 147,439.7 39,513.2 73.2 

1997 791,641.4 206,396.3 73.9 195,723.7 50,881.9 74.0 

1998 1,510,080.9 307,309.1 79.6 663,968.6 133,367.0 79.9 

1999 2,575,794.6 475,038.2 81.6 390,675.9 71,704.5 81.6 

2000 698,685.9 171,653.8 75.4 55,875.5 14,430.8 74.2 

2001 479,896.6 134,421.9 72.0 637,466.0 166,848.9 73.8 

2002 1,948,595.8 423,473.2 78.3 699,984.0 146,013.7 79.1 

2003 2,358,247.0 476,505.4 79.8 839,590.6 164,936.8 80.4 

Minimum 479,896.6 134,421.9 64.3 55,875.5 14,430.8 64.9 

Maximum 2,575,794.6 476,505.4 81.6 839,590.6 166,848.9 81.6 

Mean 1,374,425.1 318,497.6 75.2 439,971.0 101,749.6 75.5 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

64

Table 5.4 Lake Hancock Annual Average Concentrations for TN, TP, and Chlorophyll 

a

Lake Hancock 

Annual Average Concentrations for TN, TP, and Chlorophyll 

a (

μg/L) 

Year 

Measured 

TN 

Calibrated 

TN 

TMDL 

TN 

Background 

TN 

Measured 

TP 

Calibrated 

TP 

TMDL 

TP 

Background 

TP 

Measured 

Chl 

a

Calibrat

Chl 

a

1994 3,290.5 3,290.7 1,748.3 1,479.3 411.5 412.0 233.8 107.5 141.6 141.8 1995 2,845.5 2,845.7 1,229.9 963.4 453.5 452.7 219.2 114.2 160.4 159.4 1996 4,742.3 4,741.4 2,190.3 1,678.6 320.3 319.8 154.8 103.8 91.0 91.1 1997 2,257.8 2,257.2 888.7 684.7 256.7 256.1 117.2 62.7 133.1 133.3 1998 3,521.0 3,521.7 1,306.8 1,025.4 511.0 511.1 215.7 117.8 162.2 161.6 1999 7,644.5 7,643.9 2,975.7 2,212.3 637.0 636.9 258.9 172.2 160.2 160.4 2000 4,840.0 4,839.4 2,139.1 1,570.9 297.5 297.1 139.1 102.5 130.2 130.5 2001 2,760.0 2,760.0 1,225.4 938.9 767.0 767.7 379.3 211.0 65.7 64.9 2002 4,050.5 4,050.9 1,561.9 1,211.4 525.7 524.7 224.5 131.4 143.6 143.2 2003 4,573.6 4,573.8 1,754.1 1,340.7 581.6 581.3 244.0 138.8 145.5 145.6 

Minimum 2,257.8 2,257.2 888.7 684.7 256.7 256.1 117.2 62.7 65.7 64.9 

Maximum 7,644.5 7,643.9 2,975.7 2,212.3 767.0 767.7 379.3 211.0 162.2 161.6 

Mean 4,052.6 4,052.5 1,702.0 1,310.6 476.2 475.9 218.7 126.2 133.4 133.2 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 65

Lake Hancock Total Nitrogen

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Year

TN (ug/L)

TN-TM DL TN-L50-IL75 TN-PC

Figure 5.5 Lake Hancock Total Nitrogen Target TMDL, L50-IL75, and 

 Background Calibration from 1994 to 2003 

Lake Hancock Total Phosphorus

0

100

200

300

400

500

600

700

800

900

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Year

TP (ug/L)

TP-TM DL TP-L50-IL75 TP-PC

Figure 5.6 Lake Hancock Total Phosphorus Target TMDL, L50-IL75, and 

 Background Calibration from 1994 to 2003 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 66

Lake Hancock Chlorophyll a 

0

20

40

60

80

100

120

140

160

180

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Year

Chla (ug/L)

CHLA-TM DL CHLA-L50-IL75 CHLA-PC

Figure 5.7 Lake Hancock Chlorophyll a Target TMDL, L50-IL75, and 

 Background Calibration from 1994 to 2003 

Lake Hancock TSI

30

40

50

60

70

80

90

100

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003

Year

TSI

TSI-TM DL TSI-L50-IL75 TSI-PC

Figure 5.8 Lake Hancock TSI Target TMDL, L50-IL75, and 

 Background Calibration from 1994 to 2003 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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5.3 Critical Conditions 

The estimated assimilative capacity was based on annual average conditions (i.e., values 

from all four seasons in a calendar year) rather than critical/seasonal conditions because 

(a) the methodology used to determine the assimilative capacity does not lend itself very 

well to short-term assessments, (b) the Department is generally more concerned with the 

net change in overall primary productivity in the segment, which is better addressed on an 

annual basis, and (c) the methodology used to determine impairment is based on an 

annual average and requires data from all four quarters of a calendar year. 

5.4 Wasteload Allocation 

There are two NPDES facilities that discharge into Lake Lena Run, a tributary to Lake 

Hancock. The City of Auburndale Allred WWTF (FL0021466-004-DW1P/RA) operates a 

1.4 MGD annual average daily flow (AADF) that must provide advanced secondary 

treatment for any discharge into Lake Lena Run. The facility is permitted to discharge 

0.65 mgd on a monthly average basis to Lake Lena Run. The facility has a permit limit for 

total nitrogen of 6.0 mg/L as a monthly average and a report only limit for total 

phosphorus. 

The second facility is Florida Distillers Company-Auburndale, (FL0003051-003-IWB). The 

facility is permitted to discharge up to 0.5 mgd (monthly average) to Lake Lena Run 

through outfall D002. The permit includes a daily maximum total nitrogen limit of 4.4 mg/L 

and a report only limit for total phosphorus. 

Several different scenarios were examined to evaluate the contribution of the two facilities 

to the flow and loadings coming into Lake Hancock. The first scenario was for the current 

condition used for calibration. This case is referred to as Point Sources Predicted 

Calibration (PSPC). The flows and concentrations used were based on the monthly 

average data contained in the EPA NPDES database, which is the Permit Compliance 

System (PCS). This set of information was used to calibrate the WAM model and is the 

base case against which the other two scenarios will be evaluated. The second case was 

for the two facilities at their respective permit limits for flows and concentrations. This set 

of data was provided by staff from EPA Region IV. This case is referred to as Point 

Sources Maximum (PSMAX). The last scenario was with both point sources completely 

removed. This case is referred to as No Point Sources (NoPS). 

Table 5.5 contains the flow in cubic hectometers per year (CHMY) for each source. 

Sources include tributary inflow and advective inflow. The tributary inflow is generated 

within the WAM model, and the advective terms are generated within the BATHTUB 

model. The advective terms reflect the net discharge from one BATHTUB segment into 

another and are derived from water-balance calculations. The water balances in 

BATHTUB are expressed as a system of simultaneous linear equations that are solved via 

a matrix inversion to estimate the advective out-flow from each model segment. The 

advective inflow to Lake Hancock represents the sum of all the advective outflows from the 

upstream lakes. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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Table 5.5 Flow in Cubic Hectometers Per Year for Each Source 

Year 

PSPC 

TRIBFlow 

(hm3/yr)

PSPC 

ADVFlow 

(hm3/yr)

PSPC 

TOTFlow 

(hm3/yr)

PSMAX 

TRIBFlow 

(hm3/yr)

PSMAX 

ADVFlow 

(hm3/yr)

PSMAX 

TOTFlow 

(hm3/yr)

NoPS 

TRIBFlow 

(hm3/yr)

NoPS 

ADVFlow 

(hm3/yr)

NoPS 

TOTFlow 

(hm3/yr)

1994 84.3192 30.9393 115.2585 83.6379 30.9393 114.5772 82.0881 30.9393 113.0274 

1995 92.7466 34.9953 127.7419 92.5607 34.9954 127.5561 91.0104 34.9954 126.0058 

1996 66.9599 17.9993 84.9593 67.3612 17.9994 85.3606 65.818 17.9994 83.8174 

1997 127.8228 50.2292 178.0521 127.8971 50.2293 178.1264 126.3497 50.2293 176.5791 

1998 108.4174 35.7243 144.1416 108.556 35.7243 144.2803 107.0008 35.7242 142.725 

1999 56.474 12.4693 68.9433 56.8721 12.4693 69.3413 55.3333 12.4693 67.8026 

2000 45.8525 5.5804 51.4329 46.377 5.5804 51.9573 44.8298 5.5804 50.4102 

2001 66.6592 13.9542 80.6135 67.2088 13.9542 81.163 65.6655 13.9542 79.6197 

2002 115.5383 46.7394 162.2776 115.8947 46.7394 162.634 114.3425 46.7395 161.0819 

2003 106.6242 36.4613 143.0855 106.8131 36.4613 143.2744 105.2606 36.4613 141.7219 

Minimum 45.8525 5.5804 51.4329 46.377 5.5804 51.9573 44.8298 5.5804 50.4102 

Maximum 127.8228 50.2292 178.0521 127.8971 50.2293 178.1264 126.3497 50.2293 176.5791 

Mean 87.1414 28.5092 115.6506 87.3178 28.5092 115.8271 85.7699 28.5092 114.2791 

Point Sources at Current Conditions (PSPC) 

Point Sources at Permit Limits (PSMAX) 

No Point Sources (NoPS) 
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Table 5.6 shows the difference between the calibrated model total flows into the lake 

and the PSMAX and NoPS scenarios. From the table it can be seen that on average, 

the current condition has slightly less overall flow than with the two facilities operating at 

the monthly average flows specified in the permits. At the permitted monthly average 

flow, the annual average inflow to the lake increased by only 0.25 percent over the 

current condition. The elimination of both facilities would reduce the annual average 

flow into the lake by 1.30 percent (1.37 CHMY). 

Table 5.6 Difference between PSPC and PSMAX and PSPC and NoPS 

 Flow (hm3/yr) 

Year 

PSPC-PSMAX 

Flow Total 

(hm3/yr) 

PSPC-NoPS 

Flow Total 

(hm3/yr) 

PSPC-PSMAX 

Flow Total 

(hm3/yr) 

PSPC-NoPS 

Flow Total 

(hm3/yr) 

 %change %change 

1994 0.68 2.23 0.59 1.94 

1995 0.19 1.74 0.15 1.36 

1996 -0.4 1.14 -0.47 1.34 

1997 -0.07 1.47 -0.04 0.83 

1998 -0.14 1.42 -0.1 0.98 

1999 -0.4 1.14 -0.58 1.65 

2000 -0.52 1.02 -1.02 1.99 

2001 -0.55 0.99 -0.68 1.23 

2002 -0.36 1.2 -0.22 0.74 

2003 -0.19 1.36 -0.13 0.95 

Minimum -0.55 0.99 -1.02 0.74 

Maximum 0.68 2.23 0.59 1.99 

Mean -0.18 1.37 -0.25 1.3 

Table 5.7 shows the results for TP for each of the scenarios described for flow. The 

various sources of TP include tributary inflow, advective inflow, and internal loading. 

The mass attributed to internal loading is described in the section on model calibration. 

Recall, it is not just mass from internal recycling, but is actually the sum of all the TP 

mass not otherwise accounted for in the mass balance (i.e. the missing TP mass). 
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Table 5.7 Total Phosphorus Mass (kg/year) 

Year 

PSPC 

TP-TRIB 

PSPC 

TP-ADV 

PSPC 

TP-IL 

PSPC 

TP-TOT 

PSMAX 

TP-TRIB 

PSMAX 

TPADV 

PSMAX 

TP-IL 

PSMAX 

TP-TOT 

NoPS 

TP-TRIB 

No

TP-A

1994 12,901.6 13,017.8 298,084.1 324,003.6 12,845.1 13,017.8 297,866.9 323,729.8 12,513.5 13,01995 15,015.7 14,260.5 416,194.8 445,471.0 15,053.8 14,260.5 416,129.9 445,444.2 14,722.0 14,21996 11,013.8 7,923.4 128,590.5 147,527.8 11,191.6 7,923.5 128,610.0 147,725.1 10,860.9 7,921997 23,884.2 19,930.5 152,013.0 195,827.7 23,928.7 19,930.5 152,044.3 195,903.5 23,596.7 19,91998 19,501.5 20,041.7 624,853.1 664,396.3 19,546.7 20,041.7 624,877.3 664,465.8 19,215.2 20,01999 9,798.8 6,161.3 374,972.4 390,932.5 9,883.8 6,161.3 375,111.8 391,156.9 9,553.9 6,162000 8,443.0 5,335.3 42,126.1 55,904.3 8,543.6 5,335.3 42,150.5 56,029.3 8,211.5 5,332001 12,962.3 9,387.4 615,537.7 637,887.4 13,084.5 9,387.4 616,012.3 638,484.2 12,753.5 9,382002 19,492.5 19,122.8 661,821.8 700,437.0 19,579.5 19,122.8 662,076.4 700,778.7 19,247.8 19,12003 18,321.6 11,908.5 809,914.9 840,145.0 18,350.1 11,908.5 809,967.5 840,226.1 18,019.2 11,9

Minimum 8,443.0 5,335.3 42,126.1 55,904.3 8,543.6 5,335.3 42,150.5 56,029.3 8,211.5 5,33

Maximum 23,884.2 20,041.7 809,914.9 840,145.0 23,928.7 20,041.7 809,967.5 840,226.1 23,596.7 20,0

Mean 15,133.5 12,708.9 412,410.8 440,253.2 15,200.7 12,708.9 412,484.7 440,394.4 14,869.4 12,7

Point Sources at Current Conditions (PSPC) Point Sources at Permit Limits (PSMAX) No Point Sources (NoPS) 
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Table 5.8 shows the differences between the calibrated model total TP mass (kg/y) input 

into the Lake and both the PSMAX and NoPS scenarios. From the gable it can be seen 

that on average, the current condition has slightly less overall TP mass than with the two 

facilities operating at the monthly average concentrations derived from the PCS data. At 

the permitted monthly average flow, the annual average TP mass inflowing to the Lake 

increased by only 0.05 percent (141.1 kg/y). The elimination of both facilities would 

reduce the annual average TP mass into the Lake by 0.19 percent (605.6 kg/y). 

Table 5.8 Total Phosphorus Mass (kg/year) Difference between PSPC and 

 PSMAX and PSPC and NoPS 

Year 

PSPC-PSMAX 

Difference in TP as 

kg/year

PSPC-NoPS 

Difference in TP as 

kg/year

PSPC-PSMAX 

Difference in TP as 

percent

PSPC-NoPS 

Difference in TP as 

percent

1994 273.7 1016.8 0.08 0.31 

1995 26.8 645.8 0.01 0.14 

1996 -197.3 208.6 -0.13 0.14 

1997 -75.8 480.9 -0.04 0.25 

1998 -69.5 507.5 -0.01 0.08 

1999 -224.4 645.7 -0.06 0.17 

2000 -125 296.4 -0.22 0.53 

2001 -596.8 1011.6 -0.09 0.16 

2002 -341.7 633.6 -0.05 0.09 

2003 -81.1 609.1 -0.01 0.07 

Minimum -596.8 208.6 -0.22 0.07 

Maximum 273.7 1016.8 0.08 0.53 

Average -141.1 605.6 -0.05 0.19 

Table 5.9 shows the results for TN for each of the scenarios described for flow. The 

various sources of TN include tributary inflow, advective inflow, and internal loading. 

The mass attributed to internal loading is described in the section on model calibration. 

Recall, it is not just mass from internal recycling, but is actually the sum of all the TN 

mass not otherwise accounted for in the mass balance (i.e. the missing TN mass). 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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Table 5.9 Total Nitrogen Mass (kg/year) 

Year 

PSPC 

TN-TRIB 

PSPC 

TN-ADV 

PSPC 

TN-IL 

PSPC 

TN-TOT 

PSMAX 

TN-TRIB 

PSMAX 

TN-ADV 

PSMAX 

TN-IL 

PSMAX 

TN-TOT 

NoPS 

TN-TRIB 

No

TN-

1994 95,809.9 75,027.0 850,324.1 1,021,161.0 99,941.4 75,026.9 849,704.5 1,024,672.9 90,738.9 75,01995 104,720.5 61,645.1 739,972.1 906,337.7 108,193.2 61,645.1 739,856.8 909,695.1 98,999.9 61,61996 70,727.9 39,596.6 1,345,495.3 1,455,819.8 77,139.8 39,596.6 1,345,699.8 1,462,436.3 68,159.9 39,51997 134,996.1 122,453.1 534,558.1 792,007.3 141,163.9 122,453.2 534,668.1 798,285.3 132,002.4 122,1998 109,122.0 83,581.5 1,318,279.8 1,510,983.3 114,354.6 83,581.5 1,318,330.9 1,516,267.0 105,156.2 83,51999 62,991.0 39,803.0 2,474,694.5 2,577,488.5 70,235.5 39,802.9 2,475,614.5 2,585,653.0 61,372.4 39,82000 59,478.1 24,454.2 615,174.7 699,107.0 66,778.6 24,454.1 615,530.6 706,763.3 58,011.6 24,42001 78,445.6 64,208.1 337,473.9 480,127.6 85,764.2 64,208.0 337,734.1 487,706.3 76,920.5 64,22002 116,668.0 162,759.0 1,670,312.0 1,949,739.0 123,696.4 162,759.0 1,670,954.9 1,957,410.3 114,567.2 162,2003 109,343.0 88,903.1 2,161,480.5 2,359,726.5 114,456.2 88,903.0 2,161,620.8 2,364,980.0 105,257.8 88,9

Minimum 59,478.1 24,454.2 337,473.9 480,127.6 66,778.6 24,454.1 337,734.1 487,706.3 58,011.6 24,4

Maximum 134,996.1 162,759.0 2,474,694.5 2,577,488.5 141,163.9 162,759.0 2,475,614.5 2,585,653.0 132,002.4 162,

Average 94,230.2 76,243.1 1,204,776.5 1,375,249.8 100,172.4 76,243.0 1,204,971.5 1,381,386.9 91,118.7 76,2

Point Sources at Current Conditions (PSPC) Point Sources at Permit Limits (PSMAX) No Point Sources (NoPS) 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

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Table 5.10 shows the differences between the calibrated model total TN mass (kg/y) input into the 

Lake and both the PSMAX and NoPS scenarios. From the table, it can be seen that on average, 

the current condition has slightly less overall TN mass than with the two facilities operating at the 

monthly average concentrations derived from the PCS data. At the permitted monthly average flow, 

the annual average TN mass inflowing to the lake increased by only 0.59 percent (6137.2 kg/y). 

The elimination of both facilities would reduce the annual average TN mass into the lake by 0.36 

percent (4109.7 kg/y). 

Table 5.10 Total Nitrogen Mass (kg/year) Difference between PSPC and PSMAX 

 and PSPC and NoPS 

Year 

PSPC-PSMAX 

Difference in TN as 

kg/year

PSPC-NoPS 

Difference in TN 

as kg/year

PSPC-PSMAX 

Difference in TN as 

percent

PSPC-NoPS 

Difference in TN as 

percent

1994 -3511.9 6864.7 -0.34 0.67 

1995 -3357.4 6346.4 -0.37 0.7 

1996 -6616.5 3150 -0.45 0.22 

1997 -6278 3673.6 -0.79 0.46 

1998 -5283.8 4432.5 -0.35 0.29 

1999 -8164.5 4264.3 -0.32 0.17 

2000 -7656.3 2414.3 -1.1 0.35 

2001 -7578.7 1965.5 -1.58 0.41 

2002 -7671.3 3081.9 -0.39 0.16 

2003 -5253.5 4904 -0.22 0.21 

Minimum -8164.5 1965.5 -1.58 0.16 

Maximum -3357.4 6864.7 -0.22 0.7 

Average -6137.2 4109.7 -0.59 0.36 

To summarize, the annual average difference between operating the facilities at current conditions 

and at their respective permit limits was a 0.25 percent increase in total flow coming into the lake in 

combination with a 0.05 percent increase in TP mass and a 0.59 percent increase in TN mass. The 

annual average difference between the current condition and elimination of the two facilities was a 

1.3 percent reduction in total flow coming into the lake in combination with a 0.19 percent reduction 

in TP mass and a 0.36 percent reduction in TN mass. Preliminary modeling with BATHTUB 

indicates that the reduction in flow to the lake resulting from elimination of the discharge from both 

facilities had an adverse effect on the lake that more than countered the impact of the mass 

reductions. At this time, our preliminary results indicate that the annual average TSI of the lake 

would increase by 0.2 TSI units if the two facilities were eliminated. Therefore, the WLA for the two 

facilities is to maintain their currently permitted loads to the lake (note: the current permits do not 

actually include load limits for TN and TP, and these limits will need to be added to ensure that 

there are no increases in TP or TN loadings to the lake). 
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Chapter 6: DETERMINATION OF THE TMDL 

6.1 Expression and Allocation of the TMDL 

A TMDL can be expressed as the sum of all point source loads (wasteload allocations or WLAs), 

nonpoint source loads (load allocations or LAs), and an appropriate margin of safety (MOS) that 

takes into account any uncertainty about the relationship between effluent limitations and water 

quality: 

As mentioned previously, the WLA is broken out into separate subcategories for wastewater 

discharges and stormwater discharges regulated under the NPDES Program: 

 

TMDL ≅ ∑ WLAswastewater + ∑ WLAsNPDES Stormwater + ∑ LAs + MOS 

It should be noted that the various components of the TMDL equation may not sum up to the value 

of the TMDL because a) the WLA for NPDES stormwater is typically based on the percent reduction 

needed for nonpoint sources and is accounted for within the LA, and b) TMDL components can be 

expressed in different terms [for example, the WLA for stormwater is typically expressed as a 

percent reduction and the WLA for wastewater is typically expressed as a mass per day]. 

WLAs for stormwater discharges are typically expressed as “percent reduction” because it is very 

difficult to quantify the loads from MS4s (given the numerous discharge points) and to distinguish 

loads from MS4s from other nonpoint sources (given the nature of stormwater transport). The 

permitting of stormwater discharges is also different than the permitting of most wastewater point 

sources. Because stormwater discharges cannot be centrally collected, monitored and treated, 

they are not subject to the same types of effluent limitations as wastewater facilities, and instead 

are required to meet a performance standard of providing treatment to the “maximum extent 

practical” through the implementation of Best Management Practices. 

This approach is consistent with federal regulations [40 CFR § 130.2(I)], which state that TMDLs 

can be expressed in terms of mass per time (e.g. pounds per day), toxicity, or other appropriate 

measure. The TMDL for Lake Hancock is expressed in terms of pounds (lbs) per year (converted 

from kilograms per year as shown in Chapter 5, Table 5.3) and percent reductions, and represent 

the long-term annual average load of TN and TP Lake Hancock can assimilate and maintain the 

Class III narrative nutrient criterion (see Table 6.1). 

Table 6.1 Lake Hancock and Lower Saddle Creek TMDL Load Allocations 

WLA 

WBID Parameter Wastewater 

(lbs/year) 

Stormwater 

(% reduction) 

LA 

(lbs/year) MOS TMDL (lbs/year) 

Percent 

Reduction 

1623L, 

1623K TN (*1) 75.2 702,167 Implicit 702,167 75.2 

1623L, 

1623K TP (*1) 75.5 224,320 Implicit 224,320 75.5 

(*1) Note: permits for the two facilities should be modified to include monthly average loading limits for TN and TP used in the scenario 

PSMAX. 
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6.2 Load Allocation (LA) 

The required long-term annual average allowable LA is 702,167.1 lbs/year (1,923.8 lbs/day) for 

TN and 224,319.5 lbs/year (614.6 lbs/day) for TP. This corresponds to reductions from the 

existing loadings of 75.2 percent for TN and 75.5 percent for TP. Maintaining the long-term 

annual average loadings for TN and TP established as this TMDL should result in attaining the 

target lake annual average TSI of 74.4 and maintain water quality standards in Lower Saddle 

Creek. It should be noted that the LA may include loading from stormwater discharges 

regulated by the Department and the Water Management District that are not part of the NPDES 

Stormwater Program (see Appendix A). 

6.3 Wasteload Allocation (WLA) 

NPDES Wastewater Discharges 

As noted in Chapter 4, Section 4.2.1, there are two active National Pollutant Discharge 

Elimination System (NPDES) permitted facilities located within the Lake Lena Run/Creek 

watershed. Lake Lena Run is a part of the Lake Lena and Lake Lena Run sub-basin modeled 

for the Lake Hancock Basin. Based on the results discussed in Section 5.4, the annual average 

difference between operating the facilities at current conditions and at their respective permit 

limits was a 0.25 percent increase in total flow coming into the Lake in combination with a 0.05 

percent increase in TP mass and a 0.59 percent increase in TN mass. 

The annual average difference between the current condition and elimination of the two facilities 

was a 1.3 percent reduction in total flow coming into the Lake in combination with a 0.19 percent 

reduction in TP mass and a 0.36 percent reduction in TN mass. Preliminary modeling with 

BATHTUB indicates that the reduction in flow resulting from elimination of the two facilities had 

an adverse effect on the lake that more than countered the impact of the mass reductions. At 

this time, results indicate that the annual average TSI of the lake would increase by 0.2 TSI 

units if the two facilities were eliminated. Therefore, the WLA for the two NPDES facilities is to 

maintain their currently permitted loads, such that there are no increases in TP or TN loadings 

to the lake over those modeled in the scenario PSMAX discussed in Section 5.4. 

NPDES Stormwater Discharges 

The wasteload allocation for stormwater discharges is a 75.2 percent reduction in loading for TN 

and 75.5 percent for TP, which is the required percent reduction in nonpoint sources. It should 

be noted that any MS4 permittee will only be responsible for reducing the loads associated with 

stormwater outfalls for which it owns or otherwise has responsible control, and is not 

responsible for reducing other nonpoint source loads within its jurisdiction. 

6.4 Margin of Safety (MOS) 

TMDLs must address uncertainty issues by incorporating a MOS into the analysis. The MOS is 

a required component of a TMDL and accounts for the uncertainty about the relationship 

between pollutant loads and the quality of the receiving waterbody [Clean Water Act, Section 

303(d) (1) (c)]. Considerable uncertainty is usually inherent in estimating nutrient loading from 

nonpoint sources, as well as predicting water quality response. The effectiveness of 

management activities (e.g., stormwater management plans) in reducing loading is also subject 

to uncertainty. 
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The MOS can either be implicitly accounted for by choosing conservative assumptions about 

loading or water quality response, or explicitly accounted for during the allocation of loadings. 

Consistent with the recommendations of the Allocation Technical Advisory Committee (Florida 

Department of Environmental Protection, February 2001), an implicit margin of safety (MOS) was 

used in the development of the Lake Hancock and Lower Saddle Creek TMDLs. An implicit MOS 

was used for Lake Hancock because the TMDL was based on the conservative decisions 

associated with a number of the modeling assumptions and allowing for a10 TSI unit increase (5 

TSI units above natural background conditions and an additional 5 TSI units to allow for future 

changes in the watershed) in determining the assimilative capacity (i.e., loading and water quality 

response) for the lake. 

6.5 Lower Saddle Creek 

Because Lower Saddle Creek serves mainly as a conveyance system/primary outfall from Lake 

Hancock, loadings to the creek from Lake Hancock are believed to be the primary cause of the 

impairments to the creek. Thus, Lower Saddle Creek is expected to attain water quality standards 

following implementation of the Lake Hancock TMDL because the lake TMDL will require a 75.2 

percent reduction in TN and a 75.5 percent reduction in TP loadings (see Table 6.1).

 
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Chapter 7: NEXT STEPS: IMPLEMENTATION PLAN 

DEVELOPMENT AND BEYOND 

Following adoption of this TMDL by rule, the next step in the TMDL process is to develop an 

implementation plan for the TMDL, which will be a component of the Basin Management Action 

Plan for Lake Hancock and Lower Saddle Creek (and the Lake Hancock Basin). This document will 

be developed in cooperation with local stakeholders and will attempt to reach consensus on more 

detailed allocations and on how load reductions will be accomplished. 

The Basin Management Action Plan (BMAP) will include: 

• Appropriate allocations among the affected parties. 

• A description of the load reduction activities to be undertaken. 

• Timetables for project implementation and completion. 

• Funding mechanisms that may be utilized. 

• Any applicable signed agreements. 

• Local ordinances defining actions to be taken or prohibited. 

• Local water quality standards, permits, or load limitation agreements. 

• Monitoring and follow-up measures. 

It should be noted that TMDL development and implementation is an iterative process, and this 

TMDL will be re-evaluated during the BMAP development process and subsequent Watershed 

Management cycles. The Department acknowledges the uncertainty associated with TMDL 

development and allocation, particularly in estimates of nonpoint source loads and allocations for 

NPDES stormwater discharges, and fully expects that it may be further refined or revised over time. 

If any changes in the estimate of the assimilative capacity AND/OR allocation between point and 

nonpoint sources are required, the rule adopting this TMDL will be revised, thereby providing a 

point of entry for interested parties. 
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Brenner, M., T. Whitmore, M. S. Flannery, and M. W. Binford, 1993. Paleolimnological Methods for 

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of the Florida Agricultural Experiment Station. 

Brenner, M., T. Whitmore, J. H. Curtis, and C. L. Schelske, 1995. Historical Ecology of a 

Hypereutrophic Florida Lake. Journal series No. R-04021 of the Florida Agricultural Experiment 

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Water Management District. Published by the Department of Geological Sciences and the 

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the City of Lakeland, Public Works Department, Lakes and Stormwater Division, Lakeland, Florida, 

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environmental change. Environmental Science and Technology 26: 23-33.

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___, 2002. Lake Morton Water Quality Diagnostic Evaluation. Prepared by ERD Inc., Orlando, 

Florida, December, 2002. 

___, 1999. Lake Hancock Water and Nutrient Budget and Water Quality Improvement Project: 

Final Report. Prepared for the Southwest Florida Water Management District (SWFWMD) SWIM 

Program. Prepared by ERD Inc., Orlando, Florida, December, 1999. 

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Legislature on the Allocation of Total Maximum Daily Loads in Florida. Florida Department of 

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(F.A.C.), Florida Department of Environmental Protection, Division of Water Resource 

Management, Bureau of Watershed Management, Tallahassee, Florida. 

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Assessment Report. Florida Department of Environmental Protection, Division of Water Resource 

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Florida. 

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Available at http://www.dep.state.fl.us/water/wastewater/index.htm.

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; or http://www.doh.state.fl.us/environment/OSTDS/statistics/ostdsstatistics.htm. 
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Florida Department of Transportation, 1999. Florida Land Use, Cover and Forms Classification 

Systen (FLUCCS). Florida Department of Transportation Thematic Mapping Section. 

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Resource Management, Watershed Assessment Section, Tallahassee, Florida, February, 2005. 

Gao, X., 2005. Nutrient and Unionized Ammonia Total Maximum Daily Loads for Lake Jesup, 

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Resource Management, Watershed Assessment Section, Tallahassee, Florida, August, 2005. 

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County, Florida. WRI Open File Report 81-131. Prepared by USGS in cooperation with the 

Southwest Florida Water Management District 

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September, 2003. 

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Water Quality Improvement Project. Final Report to the Southwest Florida Water Management 

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National Weather Service, 2004. National Weather Service, National Climatic Data Center, Climate 

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 82

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DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 83

Appendices 

Appendix A: Background Information on Federal and State Stormwater 

 Programs 

In 1982, Florida became the first state in the country to implement statewide regulations to address 

the issue of nonpoint source pollution by requiring new development and redevelopment to treat 

stormwater before it is discharged. The Stormwater Rule, as authorized in Chapter 403, F.S., was 

established as a technology-based program that relies on the implementation of BMPs that are 

designed to achieve a specific level of treatment (i.e., performance standards) as set forth in 

Chapter 62-40, F.A.C. 

The rule requires the state’s water management districts (WMDs) to establish stormwater pollutant 

load reduction goals (PLRGs) and adopt them as part of a SWIM plan, other watershed plan, or 

rule. Stormwater PLRGs are a major component of the load allocation part of a TMDL. To date, 

stormwater PLRGs have been established for Tampa Bay, Lake Thonotosassa, the Winter Haven 

Chain of Lakes, the Everglades, Lake Okeechobee, and Lake Apopka. At this time, no PLRG has 

been developed for Lake Hancock. 

In 1987, the U.S. Congress established Section 402(p) as part of the federal Clean Water Act 

Reauthorization. This section of the law amended the scope of the federal NPDES permitting 

program to designate certain stormwater discharges as “point sources” of pollution. The EPA 

promulgated regulations and began implementation of the Phase I NPDES stormwater program in 

1990. These stormwater discharges include certain discharges that are associated with industrial 

activities designated by specific Standard Industrial Classification (SIC) codes, construction sites 

disturbing five or more acres of land, and master drainage systems of local governments with a 

population above 100,000, which are better known as municipal separate storm sewer systems 

(MS4s). However, because the master drainage systems of most local governments in Florida are 

interconnected, the EPA implemented Phase I of the MS4 permitting program on a countywide 

basis, which brought in all cities (incorporated areas), Chapter 298 urban water control districts, and 

the Florida Department of Transportation throughout the fifteen counties meeting the population 

criteria. The Department received authorization to implement the NPDES stormwater program in 

2000. 

An important difference between the NPDES and other state stormwater permitting programs is that 

the NPDES program covers both new and existing discharges, while the other state programs focus 

on new discharges. Additionally, Phase II of the NPDES Program, implemented in 2003, expands 

the need for these permits to construction sites between one and five acres, and to local 

governments with as few as 1,000 people. While these urban stormwater discharges are now 

technically referred to as “point sources” for the purpose of regulation, they are still diffuse sources 

of pollution that cannot be easily collected and treated by a central treatment facility similar to other 

point sources of pollution, such as domestic and industrial wastewater discharges. It should be 

noted that all MS4 permits issued in Florida include a re-opener clause that allows permit revisions 

to implement TMDLs when the implementation plan is formally adopted.
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 84

Appendix B: TN, TP, Chlorophyll a, and DO Monitoring Data Used 

 in the TMDL Analysis for Lake Hancock and Lower 

 Saddle Creek 

Lake Hancock TN Data 

WBID Station Date Time Depth

Storet 

Code 

TN

(mg/L) R-Code 

1623L 21FLPOLKHANCOCK1 4/9/1992 1141 0.50 600 11.22 

1623L 21FLPOLKHANCOCK1 10/7/1992 1527 0.70 600 4.07 

1623L 21FLPOLKHANCOCK1 3/31/1993 1530 0.70 600 12.03 

1623L 21FLPOLKHANCOCK1 10/7/1993 1107 0.70 600 2.04 

1623L 21FLPOLKHANCOCK1 12/6/1993 1053 0.70 600 4.02 

1623L 21FLPOLKHANCOCK1 12/20/1993 1043 0.70 600 4.30 

1623L 21FLPOLKHANCOCK1 4/12/1994 1210 0.60 600 4.87 

1623L 21FLPOLKHANCOCK1 10/5/1994 1205 0.90 600 1.71 

1623L 21FLPOLKHANCOCK1 4/5/1995 1230 0.80 600 3.13 

1623L 21FLPOLKHANCOCK1 11/8/1995 844 0.80 600 2.56 

1623L 21FLPOLKHANCOCK1 5/8/1996 1200 0.80 600 4.99 

1623L 21FLSWFDSTA0192 8/1/1996 1535 0.50 600 4.82 

1623L 21FLPOLKHANCOCK1 11/13/1996 1248 2.62 600 4.42 

1623L 21FLPOLKHANCOCK1 5/7/1997 1150 0.10 600 4.63 

1623L 21FLPOLKHANCOCK1 10/30/1997 1145 0.70 600 1.98 

1623L 21FLPOLKHANCOCK1 5/7/1998 1245 0.80 600 1.89 

1623L 21FLPOLKHANCOCK1 11/9/1998 1015 0.60 600 5.15 

1623L 21FLPOLKHANCOCK1 5/11/1999 900 0.50 600 9.80 

1623L 21FLPOLKHANCOCK1 11/9/1999 830 0.49 600 5.49 

1623L 21FLPOLKHANCOCK1 5/3/2000 815 0.30 600 4.11 

1623L 21FLPOLKHANCOCK1 11/16/2000 1200 0.40 600 5.57 

1623L 21FLPOLKHANCOCK1 11/20/2001 1400 0.50 600 2.76 

1623L 21FLPOLKHANCOCK A 1/16/2002 845 0.50 600 4.24 

1623L 21FLPOLKHANCOCK B 1/16/2002 915 0.50 600 3.00 

1623L 21FLPOLKHANCOCK C 1/16/2002 945 0.50 600 3.00 

1623L 21FLPOLKHANCOCK D 1/16/2002 1005 0.50 600 4.19 

1623L 21FLPOLKHANCOCK A 2/5/2002 1345 0.50 600 5.58 

1623L 21FLPOLKHANCOCK B 2/5/2002 1410 0.50 600 2.86 

1623L 21FLPOLKHANCOCK C 2/5/2002 1435 0.50 600 4.15 

1623L 21FLPOLKHANCOCK D 2/5/2002 1500 0.50 600 5.11 

1623L 21FLPOLKHANCOCK A 3/7/2002 1355 0.50 600 7.93 

1623L 21FLPOLKHANCOCK B 3/7/2002 1400 0.50 600 4.54 

1623L 21FLPOLKHANCOCK C 3/7/2002 1416 0.50 600 4.60 

1623L 21FLPOLKHANCOCK D 3/7/2002 1430 0.50 600 8.06 

1623L 21FLPOLKHANCOCK H-10 8/22/2002 810 0.50 600 2.03 

1623L 21FLPOLKHANCOCK H-16 8/22/2002 840 0.50 600 4.06 

1623L 21FLPOLKHANCOCK H-17 8/22/2002 820 0.50 600 4.46 

1623L 21FLPOLKHANCOCK H-18 8/22/2002 830 0.50 600 4.78 

1623L 21FLPOLKHANCOCK H-2 8/22/2002 805 0.50 600 1.69 

1623L 21FLPOLKHANCOCK H-23 8/22/2002 845 0.50 600 2.88 

1623L 21FLPOLKHANCOCK H-26 8/22/2002 920 0.50 600 3.99 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 85

WBID Station Date Time Depth

Storet 

Code 

TN

(mg/L) R-Code 

1623L 21FLPOLKHANCOCK H-37 8/22/2002 855 0.50 600 4.92 

1623L 21FLPOLKHANCOCK H-4 8/22/2002 750 0.50 600 1.48 

1623L 21FLPOLKHANCOCK H-52 8/22/2002 930 0.50 600 4.94 

1623L 21FLPOLKHANCOCK H-59 8/22/2002 945 0.50 600 4.47 

1623L 21FLPOLKHANCOCK H-62 8/22/2002 1000 0.50 600 4.41 

1623L 21FLPOLKHANCOCK H-12 11/18/2002 1305 0.50 600 2.43 

1623L 21FLPOLKHANCOCK H-16 11/18/2002 945 0.20 600 3.25 

1623L 21FLPOLKHANCOCK H-19 11/18/2002 1255 0.50 600 2.55 

1623L 21FLPOLKHANCOCK H-2 11/18/2002 925 0.40 600 1.19 

1623L 21FLPOLKHANCOCK H-23 11/18/2002 1005 0.50 600 3.90 

1623L 21FLPOLKHANCOCK H-25 11/18/2002 1240 0.40 600 3.44 

1623L 21FLPOLKHANCOCK H-30 11/18/2002 1020 0.50 600 4.57 

1623L 21FLPOLKHANCOCK H-33 11/18/2002 1150 0.50 600 3.26 

1623L 21FLPOLKHANCOCK H-36 11/18/2002 1035 0.40 600 4.81 

1623L 21FLPOLKHANCOCK H-40 11/18/2002 1130 0.40 600 1.83 

1623L 21FLPOLKHANCOCK H-53 11/18/2002 1225 0.50 600 4.01 

1623L 21FLPOLKHANCOCK H-55 11/18/2002 1210 0.40 600 3.99 

1623L 21FLTPA 25020276 2/4/2003 940 0.20 600 1.51 + 

1623L 21FLPOLKHANCOCK H-16 2/13/2003 825 0.50 600 2.73 

1623L 21FLPOLKHANCOCK H-17 2/13/2003 840 0.50 600 3.38 

1623L 21FLPOLKHANCOCK H-22 2/13/2003 915 0.45 600 3.38 

1623L 21FLPOLKHANCOCK H-25 2/13/2003 900 0.50 600 3.48 

1623L 21FLPOLKHANCOCK H-29 2/13/2003 920 0.50 600 3.82 

1623L 21FLPOLKHANCOCK H-30 2/13/2003 945 0.50 600 3.64 

1623L 21FLPOLKHANCOCK H-36 2/13/2003 935 0.45 600 3.83 

1623L 21FLPOLKHANCOCK H-41 2/13/2003 1040 0.50 600 2.13 

1623L 21FLPOLKHANCOCK H-45 2/13/2003 1110 0.50 600 3.39 

1623L 21FLPOLKHANCOCK H-47 2/13/2003 1055 0.50 600 2.26 

1623L 21FLPOLKHANCOCK H-59 2/13/2003 1120 0.50 600 3.05 

1623L 21FLPOLKHANCOCK H-62 2/13/2003 1140 0.50 600 2.95 

1623L 21FLTPA 25020276 4/22/2003 1110 0.20 600 4.00 + 

1623L 21FLPOLKHANCOCK H-24 5/20/2003 1150 0.50 600 7.04 

1623L 21FLPOLKHANCOCK H-25 5/20/2003 1140 0.50 600 6.56 

1623L 21FLPOLKHANCOCK H-31 5/20/2003 1200 0.50 600 7.38 

1623L 21FLPOLKHANCOCK H-32 5/20/2003 1210 0.50 600 5.45 

1623L 21FLPOLKHANCOCK H-37 5/20/2003 1010 0.50 600 7.20 

1623L 21FLPOLKHANCOCK H-38 5/20/2003 1000 0.50 600 6.30 

1623L 21FLPOLKHANCOCK H-4 5/20/2003 1115 0.50 600 2.31 

1623L 21FLPOLKHANCOCK H-40 5/20/2003 845 0.50 600 7.27 

1623L 21FLPOLKHANCOCK H-47 5/20/2003 900 0.50 600 5.72 

1623L 21FLPOLKHANCOCK H-52 5/20/2003 950 0.50 600 7.28 

1623L 21FLPOLKHANCOCK H-53 5/20/2003 940 0.50 600 6.83 

1623L 21FLPOLKHANCOCK H-56 5/20/2003 920 0.40 600 4.81 

1623L 21FLTPA 25020276 8/18/2003 900 0.20 600 2.60 + 

1623L 21FLPOLKHANCOCK H-18 8/20/2003 840 0.50 600 4.19 

1623L 21FLPOLKHANCOCK H-23 8/20/2003 855 0.50 600 3.01 

1623L 21FLPOLKHANCOCK H-24 8/20/2003 850 0.50 600 5.26 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 86

WBID Station Date Time Depth

Storet 

Code 

TN

(mg/L) R-Code 

1623L 21FLPOLKHANCOCK H-37 8/20/2003 910 0.50 600 3.69 

1623L 21FLPOLKHANCOCK H-38 8/20/2003 920 0.50 600 3.34 

1623L 21FLPOLKHANCOCK H-39 8/20/2003 930 0.50 600 5.54 

1623L 21FLPOLKHANCOCK H-4 8/20/2003 820 0.50 600 1.37 

1623L 21FLPOLKHANCOCK H-47 8/20/2003 1050 0.50 600 4.09 

1623L 21FLPOLKHANCOCK H-48 8/20/2003 1040 0.50 600 3.09 

1623L 21FLPOLKHANCOCK H-51 8/20/2003 1000 0.50 600 3.26 

1623L 21FLPOLKHANCOCK H-59 8/20/2003 1015 0.50 600 3.42 

1623L 21FLPOLKHANCOCK H-61 8/20/2003 1025 0.50 600 4.72 

1623L 21FLTPA 25020276 11/3/2003 1040 0.20 600 3.30 + 

1623L 21FLPOLKHANCOCK H-11 11/18/2003 1150 0.50 600 4.13 

1623L 21FLPOLKHANCOCK H-16 11/18/2003 1130 0.50 600 5.76 

1623L 21FLPOLKHANCOCK H-22 11/18/2003 1120 0.50 600 4.42 

1623L 21FLPOLKHANCOCK H-3 11/18/2003 1140 0.50 600 4.87 

1623L 21FLPOLKHANCOCK H-30 11/18/2003 1110 0.50 600 4.79 

1623L 21FLPOLKHANCOCK H-31 11/18/2003 1100 0.50 600 4.89 

1623L 21FLPOLKHANCOCK H-34 11/18/2003 945 0.50 600 4.26 

1623L 21FLPOLKHANCOCK H-40 11/18/2003 955 0.50 600 5.13 

1623L 21FLPOLKHANCOCK H-43 11/18/2003 1010 0.50 600 5.07 

1623L 21FLPOLKHANCOCK H-48 11/18/2003 905 0.50 600 5.13 

1623L 21FLPOLKHANCOCK H-49 11/18/2003 920 0.50 600 3.09 

1623L 21FLPOLKHANCOCK H-54 11/18/2003 850 0.50 600 4.01 

1623L 21FLPOLKHANCOCK H-11 2/19/2004 1120 0.50 600 4.06 + 

1623L 21FLPOLKHANCOCK H-22 2/19/2004 1055 0.50 600 4.70 + 

1623L 21FLPOLKHANCOCK H-24 2/19/2004 1110 0.50 600 3.64 + 

1623L 21FLPOLKHANCOCK H-30 2/19/2004 1045 0.50 600 4.86 + 

1623L 21FLPOLKHANCOCK H-33 2/19/2004 950 0.50 600 4.89 + 

1623L 21FLPOLKHANCOCK H-34 2/19/2004 1000 0.50 600 4.70 + 

1623L 21FLPOLKHANCOCK H-36 2/19/2004 920 0.50 600 5.13 + 

1623L 21FLPOLKHANCOCK H-37 2/19/2004 935 0.50 600 4.39 + 

1623L 21FLPOLKHANCOCK H-44 2/19/2004 905 0.50 600 5.01 + 

1623L 21FLPOLKHANCOCK H-59 2/19/2004 850 0.50 600 3.95 + 

1623L 21FLPOLKHANCOCK H-62 2/19/2004 830 0.50 600 4.65 + 

1623L 21FLPOLKHANCOCK H-9 2/19/2004 1130 0.50 600 4.91 + 

1623L 21FLPOLKHANCOCK H-12 5/5/2004 950 0.50 600 4.79 + 

1623L 21FLPOLKHANCOCK H-22 5/5/2004 925 0.40 600 8.53 + 

1623L 21FLPOLKHANCOCK H-3 5/5/2004 940 0.40 600 7.30 + 

1623L 21FLPOLKHANCOCK H-31 5/5/2004 835 0.50 600 8.40 + 

1623L 21FLPOLKHANCOCK H-33 5/5/2004 825 0.50 600 6.15 + 

1623L 21FLPOLKHANCOCK H-36 5/5/2004 915 0.50 600 8.64 + 

1623L 21FLPOLKHANCOCK H-40 5/5/2004 815 0.50 600 7.06 + 

1623L 21FLPOLKHANCOCK H-43 5/5/2004 910 0.50 600 8.40 + 

1623L 21FLPOLKHANCOCK H-47 5/5/2004 805 0.50 600 8.11 + 

1623L 21FLPOLKHANCOCK H-50 5/5/2004 900 0.50 600 4.98 + 

1623L 21FLPOLKHANCOCK H-54 5/5/2004 755 0.50 600 7.85 + 

1623L 21FLPOLKHANCOCK H-62 5/5/2004 745 0.50 600 7.20 + 

+ : Calculated value. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 87

Lake Hancock TP Data 

WBID Station Date Time Depth

Storet 

Code 

TP

(mg/L) R-Code 

1623L 21FLPOLKHANCOCK1 4/9/1992 1141 0.50 665 0.94 

1623L 21FLPOLKHANCOCK1 10/7/1992 1527 0.70 665 0.37 

1623L 21FLPOLKHANCOCK1 3/31/1993 1530 0.70 665 0.71 

1623L 21FLPOLKHANCOCK1 10/7/1993 1107 0.70 665 0.20 

1623L 21FLPOLKHANCOCK1 12/6/1993 1053 0.70 665 0.17 

1623L 21FLPOLKHANCOCK1 12/20/1993 1043 0.70 665 0.20 

1623L 21FLPOLKHANCOCK1 4/12/1994 1210 0.60 665 0.47 

1623L 21FLPOLKHANCOCK1 10/5/1994 1205 0.90 665 0.36 

1623L 21FLPOLKHANCOCK1 4/5/1995 1230 0.80 665 0.42 

1623L 21FLPOLKHANCOCK1 11/8/1995 844 0.80 665 0.49 

1623L 21FLPOLKHANCOCK1 5/8/1996 1200 0.80 665 0.51 

1623L 21FLSWFDSTA0192 8/1/1996 1535 0.50 665 0.04 

1623L 21FLPOLKHANCOCK1 11/13/1996 1248 2.62 665 0.42 

1623L 21FLPOLKHANCOCK1 5/7/1997 1150 0.10 665 0.43 

1623L 21FLPOLKHANCOCK1 10/30/1997 1145 0.70 665 0.11 

1623L 21FLPOLKHANCOCK1 5/7/1998 1245 0.80 665 0.54 

1623L 21FLPOLKHANCOCK1 11/9/1998 1015 0.60 665 0.49 

1623L 21FLPOLKHANCOCK1 5/11/1999 900 0.50 665 0.75 

1623L 21FLPOLKHANCOCK1 11/9/1999 830 0.49 665 0.53 

1623L 21FLPOLKHANCOCK1 5/3/2000 815 0.30 665 0.36 

1623L 21FLPOLKHANCOCK1 11/16/2000 1200 0.40 665 0.23 

1623L 21FLPOLKHANCOCK1 11/20/2001 1400 0.50 665 0.77 

1623L 21FLPOLKHANCOCK A 1/16/2002 845 0.50 665 0.76 

1623L 21FLPOLKHANCOCK B 1/16/2002 915 0.50 665 0.97 

1623L 21FLPOLKHANCOCK C 1/16/2002 945 0.50 665 0.73 

1623L 21FLPOLKHANCOCK D 1/16/2002 1005 0.50 665 0.74 

1623L 21FLPOLKHANCOCK A 2/5/2002 1345 0.50 665 0.81 

1623L 21FLPOLKHANCOCK B 2/5/2002 1410 0.50 665 1.01 

1623L 21FLPOLKHANCOCK C 2/5/2002 1435 0.50 665 0.73 

1623L 21FLPOLKHANCOCK D 2/5/2002 1500 0.50 665 0.76 

1623L 21FLPOLKHANCOCK A 3/7/2002 1355 0.50 665 0.82 

1623L 21FLPOLKHANCOCK B 3/7/2002 1400 0.50 665 0.80 

1623L 21FLPOLKHANCOCK C 3/7/2002 1416 0.50 665 0.71 

1623L 21FLPOLKHANCOCK D 3/7/2002 1430 0.50 665 0.82 

1623L 21FLPOLKHANCOCK H-10 8/22/2002 810 0.50 665 0.44 

1623L 21FLPOLKHANCOCK H-16 8/22/2002 840 0.50 665 0.39 

1623L 21FLPOLKHANCOCK H-17 8/22/2002 820 0.50 665 0.34 

1623L 21FLPOLKHANCOCK H-18 8/22/2002 830 0.50 665 0.42 

1623L 21FLPOLKHANCOCK H-2 8/22/2002 805 0.50 665 0.50 

1623L 21FLPOLKHANCOCK H-23 8/22/2002 845 0.50 665 0.38 

1623L 21FLPOLKHANCOCK H-26 8/22/2002 920 0.50 665 0.34 

1623L 21FLPOLKHANCOCK H-37 8/22/2002 855 0.50 665 0.39 

1623L 21FLPOLKHANCOCK H-4 8/22/2002 750 0.50 665 0.54 

1623L 21FLPOLKHANCOCK H-52 8/22/2002 930 0.50 665 0.37 

1623L 21FLPOLKHANCOCK H-59 8/22/2002 945 0.50 665 0.30 A 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 88

WBID Station Date Time Depth

Storet 

Code 

TP

(mg/L) R-Code 

1623L 21FLPOLKHANCOCK H-62 8/22/2002 1000 0.50 665 0.33 

1623L 21FLPOLKHANCOCK H-12 11/18/2002 1305 0.50 665 0.34 

1623L 21FLPOLKHANCOCK H-16 11/18/2002 945 0.20 665 0.43 

1623L 21FLPOLKHANCOCK H-19 11/18/2002 1255 0.50 665 0.42 

1623L 21FLPOLKHANCOCK H-2 11/18/2002 925 0.40 665 0.45 

1623L 21FLPOLKHANCOCK H-23 11/18/2002 1005 0.50 665 0.41 

1623L 21FLPOLKHANCOCK H-25 11/18/2002 1240 0.40 665 0.43 

1623L 21FLPOLKHANCOCK H-30 11/18/2002 1020 0.50 665 0.48 

1623L 21FLPOLKHANCOCK H-33 11/18/2002 1150 0.50 665 0.37 

1623L 21FLPOLKHANCOCK H-36 11/18/2002 1035 0.40 665 0.49 

1623L 21FLPOLKHANCOCK H-40 11/18/2002 1130 0.40 665 0.10 

1623L 21FLPOLKHANCOCK H-53 11/18/2002 1225 0.50 665 0.41 

1623L 21FLPOLKHANCOCK H-55 11/18/2002 1210 0.40 665 0.35 

1623L 21FLTPA 25020276 2/4/2003 940 0.20 665 0.43 

1623L 21FLPOLKHANCOCK H-16 2/13/2003 825 0.50 665 0.56 

1623L 21FLPOLKHANCOCK H-17 2/13/2003 840 0.50 665 0.56 

1623L 21FLPOLKHANCOCK H-22 2/13/2003 915 0.45 665 0.59 

1623L 21FLPOLKHANCOCK H-25 2/13/2003 900 0.50 665 0.55 

1623L 21FLPOLKHANCOCK H-29 2/13/2003 920 0.50 665 0.62 

1623L 21FLPOLKHANCOCK H-30 2/13/2003 945 0.50 665 0.59 

1623L 21FLPOLKHANCOCK H-36 2/13/2003 935 0.45 665 0.63 

1623L 21FLPOLKHANCOCK H-41 2/13/2003 1040 0.50 665 0.42 

1623L 21FLPOLKHANCOCK H-45 2/13/2003 1110 0.50 665 0.58 

1623L 21FLPOLKHANCOCK H-47 2/13/2003 1055 0.50 665 0.46 

1623L 21FLPOLKHANCOCK H-59 2/13/2003 1120 0.50 665 0.57 

1623L 21FLPOLKHANCOCK H-62 2/13/2003 1140 0.50 665 0.54 

1623L 21FLTPA 25020276 4/22/2003 1110 0.20 665 0.68 

1623L 21FLPOLKHANCOCK H-24 5/20/2003 1150 0.50 665 0.95 

1623L 21FLPOLKHANCOCK H-25 5/20/2003 1140 0.50 665 0.83 

1623L 21FLPOLKHANCOCK H-31 5/20/2003 1200 0.50 665 0.95 

1623L 21FLPOLKHANCOCK H-32 5/20/2003 1210 0.50 665 0.89 

1623L 21FLPOLKHANCOCK H-37 5/20/2003 1010 0.50 665 0.88 

1623L 21FLPOLKHANCOCK H-37 5/20/2003 1015 0.50 665 0.89 

1623L 21FLPOLKHANCOCK H-38 5/20/2003 1000 0.50 665 0.87 

1623L 21FLPOLKHANCOCK H-4 5/20/2003 1115 0.50 665 0.52 

1623L 21FLPOLKHANCOCK H-40 5/20/2003 845 0.50 665 0.94 

1623L 21FLPOLKHANCOCK H-47 5/20/2003 900 0.50 665 0.67 

1623L 21FLPOLKHANCOCK H-52 5/20/2003 950 0.50 665 0.91 

1623L 21FLPOLKHANCOCK H-53 5/20/2003 940 0.50 665 0.85 

1623L 21FLPOLKHANCOCK H-56 5/20/2003 920 0.40 665 0.66 

1623L 21FLTPA 25020276 8/18/2003 900 0.20 665 0.35 

1623L 21FLPOLKHANCOCK H-18 8/20/2003 840 0.50 665 0.41 

1623L 21FLPOLKHANCOCK H-23 8/20/2003 855 0.50 665 0.49 

1623L 21FLPOLKHANCOCK H-24 8/20/2003 850 0.50 665 0.54 

1623L 21FLPOLKHANCOCK H-37 8/20/2003 910 0.50 665 0.41 

1623L 21FLPOLKHANCOCK H-38 8/20/2003 920 0.50 665 0.40 

1623L 21FLPOLKHANCOCK H-39 8/20/2003 930 0.50 665 0.55 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 89

WBID Station Date Time Depth

Storet 

Code 

TP

(mg/L) R-Code 

1623L 21FLPOLKHANCOCK H-4 8/20/2003 820 0.50 665 0.40 

1623L 21FLPOLKHANCOCK H-47 8/20/2003 1050 0.50 665 0.38 

1623L 21FLPOLKHANCOCK H-48 8/20/2003 1040 0.50 665 0.33 

1623L 21FLPOLKHANCOCK H-51 8/20/2003 1000 0.50 665 0.36 

1623L 21FLPOLKHANCOCK H-59 8/20/2003 1015 0.50 665 0.37 

1623L 21FLPOLKHANCOCK H-61 8/20/2003 1025 0.50 665 0.49 

1623L 21FLTPA 25020276 11/3/2003 1040 0.20 665 0.50 

1623L 21FLPOLKHANCOCK H-11 11/18/2003 1150 0.50 665 0.46 

1623L 21FLPOLKHANCOCK H-16 11/18/2003 1130 0.50 665 0.58 

1623L 21FLPOLKHANCOCK H-22 11/18/2003 1120 0.50 665 0.52 

1623L 21FLPOLKHANCOCK H-3 11/18/2003 1140 0.50 665 0.50 

1623L 21FLPOLKHANCOCK H-30 11/18/2003 1110 0.50 665 0.41 

1623L 21FLPOLKHANCOCK H-31 11/18/2003 1100 0.50 665 0.46 

1623L 21FLPOLKHANCOCK H-34 11/18/2003 945 0.50 665 0.42 

1623L 21FLPOLKHANCOCK H-40 11/18/2003 955 0.50 665 0.53 

1623L 21FLPOLKHANCOCK H-43 11/18/2003 1010 0.50 665 0.45 

1623L 21FLPOLKHANCOCK H-48 11/18/2003 905 0.50 665 0.52 

1623L 21FLPOLKHANCOCK H-49 11/18/2003 920 0.50 665 0.40 

1623L 21FLPOLKHANCOCK H-54 11/18/2003 850 0.50 665 0.40 

1623L 21FLPOLKHANCOCK H-11 2/19/2004 1120 0.50 665 0.27 

1623L 21FLPOLKHANCOCK H-22 2/19/2004 1055 0.50 665 0.36 

1623L 21FLPOLKHANCOCK H-24 2/19/2004 1110 0.50 665 0.27 

1623L 21FLPOLKHANCOCK H-30 2/19/2004 1045 0.50 665 0.41 

1623L 21FLPOLKHANCOCK H-33 2/19/2004 950 0.50 665 0.33 

1623L 21FLPOLKHANCOCK H-34 2/19/2004 1000 0.50 665 0.36 

1623L 21FLPOLKHANCOCK H-36 2/19/2004 920 0.50 665 0.43 

1623L 21FLPOLKHANCOCK H-37 2/19/2004 935 0.50 665 0.35 

1623L 21FLPOLKHANCOCK H-44 2/19/2004 905 0.50 665 0.37 

1623L 21FLPOLKHANCOCK H-59 2/19/2004 850 0.50 665 0.40 

1623L 21FLPOLKHANCOCK H-62 2/19/2004 830 0.50 665 0.34 

1623L 21FLPOLKHANCOCK H-9 2/19/2004 1130 0.50 665 0.39 

1623L 21FLPOLKHANCOCK H-12 5/5/2004 950 0.50 665 0.36 

1623L 21FLPOLKHANCOCK H-22 5/5/2004 925 0.40 665 0.64 

1623L 21FLPOLKHANCOCK H-3 5/5/2004 940 0.40 665 0.62 

1623L 21FLPOLKHANCOCK H-31 5/5/2004 835 0.50 665 0.55 

1623L 21FLPOLKHANCOCK H-33 5/5/2004 825 0.50 665 0.60 

1623L 21FLPOLKHANCOCK H-36 5/5/2004 915 0.50 665 0.57 

1623L 21FLPOLKHANCOCK H-40 5/5/2004 815 0.50 665 0.61 

1623L 21FLPOLKHANCOCK H-43 5/5/2004 910 0.50 665 0.61 

1623L 21FLPOLKHANCOCK H-47 5/5/2004 805 0.50 665 0.65 

1623L 21FLPOLKHANCOCK H-50 5/5/2004 900 0.50 665 0.55 

1623L 21FLPOLKHANCOCK H-54 5/5/2004 755 0.50 665 0.51 

1623L 21FLPOLKHANCOCK H-62 5/5/2004 745 0.50 665 0.56 

A: Value reported is the mean of two or more determinations. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 90

Lake Hancock Chlorophyll a Data 

WBID Station Date Time Depth

Storet 

Code 

Chla 

(μg/L) R-Code 

1623L 21FLPOLKHANCOCK1 4/9/1992 1141 1.64 32210 310.5 

1623L 21FLPOLKHANCOCK1 10/7/1992 1527 4.59 32210 131.8 

1623L 21FLPOLKHANCOCK1 3/31/1993 1530 2.30 32210 173.1 

1623L 21FLPOLKHANCOCK1 10/7/1993 1107 2.30 32210 66.4 

1623L 21FLPOLKHANCOCK1 12/6/1993 1053 2.30 32210 87.8 

1623L 21FLPOLKHANCOCK1 12/20/1993 1043 2.30 32210 67.3 

1623L 21FLPOLKHANCOCK1 4/12/1994 1210 1.97 32210 204.5 

1623L 21FLPOLKHANCOCK1 10/5/1994 1205 2.95 32210 78.8 

1623L 21FLPOLKHANCOCK1 4/5/1995 1230 2.62 32210 158.9 

1623L 21FLPOLKHANCOCK1 11/8/1995 844 2.62 32210 161.8 

1623L 21FLPOLKHANCOCK1 5/8/1996 1200 2.62 32210 186.6 

1623L 21FLSWFDSTA0192 8/1/1996 1535 0.50 32210 24.1 

1623L 21FLSWFDSTA0192 8/1/1996 1535 0.50 32211 23.3 

1623L 21FLPOLKHANCOCK1 11/13/1996 1248 2.62 32210 130.1 

1623L 21FLSWFDSTA0192 1/13/1997 2500 0.50 32210 171.3 

1623L 21FLSWFDSTA0192 1/13/1997 2500 0.50 32211 137.8 

1623L 21FLPOLKHANCOCK1 5/7/1997 1150 0.33 32210 152.0 

1623L 21FLPOLKHANCOCK1 10/30/1997 1145 2.30 32210 71.5 

1623L 21FLPOLKHANCOCK1 5/7/1998 1245 0.80 32210 86.5 

1623L 21FLPOLKHANCOCK1 11/9/1998 1015 1.97 32210 237.9 

1623L 21FLPOLKHANCOCK1 5/11/1999 900 0.50 32223 216.3 

1623L 21FLPOLKHANCOCK1 11/9/1999 830 0.49 32223 104.1 

1623L 21FLPOLKHANCOCK1 5/3/2000 815 0.30 32223 144.2 

1623L 21FLPOLKHANCOCK1 11/16/2000 1200 0.40 32223 116.2 

1623L 21FLPOLKHANCOCK1 11/20/2001 1400 0.50 32223 65.7 

1623L 21FLPOLKHANCOCK A 1/16/2002 845 0.50 32223 152.2 E 

1623L 21FLPOLKHANCOCK B 1/16/2002 915 0.50 32223 34.4 E 

1623L 21FLPOLKHANCOCK C 1/16/2002 945 0.50 32223 76.9 E 

1623L 21FLPOLKHANCOCK D 1/16/2002 1005 0.50 32223 146.9 

1623L 21FLPOLKHANCOCK A 2/5/2002 1345 0.50 32223 175.2 E 

1623L 21FLPOLKHANCOCK B 2/5/2002 1410 0.50 32223 53.7 E 

1623L 21FLPOLKHANCOCK C 2/5/2002 1435 0.50 32223 106.1 E 

1623L 21FLPOLKHANCOCK D 2/5/2002 1500 0.50 32223 184.2 E 

1623L 21FLPOLKHANCOCK A 3/7/2002 1355 0.50 32223 483.0 

1623L 21FLPOLKHANCOCK B 3/7/2002 1400 0.50 32223 166.0 

1623L 21FLPOLKHANCOCK C 3/7/2002 1416 0.50 32223 348.0 

1623L 21FLPOLKHANCOCK D 3/7/2002 1430 0.50 32223 558.0 

1623L 21FLPOLKHANCOCK H-10 8/22/2002 810 0.50 32223 43.3 

1623L 21FLPOLKHANCOCK H-16 8/22/2002 840 0.50 32223 128.2 

1623L 21FLPOLKHANCOCK H-17 8/22/2002 820 0.50 32223 172.2 

1623L 21FLPOLKHANCOCK H-18 8/22/2002 830 0.50 32223 164.2 

1623L 21FLPOLKHANCOCK H-2 8/22/2002 805 0.50 32223 17.6 

1623L 21FLPOLKHANCOCK H-23 8/22/2002 845 0.50 32223 88.1 

1623L 21FLPOLKHANCOCK H-26 8/22/2002 920 0.50 32223 128.2 

1623L 21FLPOLKHANCOCK H-37 8/22/2002 855 0.50 32223 144.2 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 91

WBID Station Date Time Depth

Storet 

Code 

Chla 

(μg/L) R-Code 

1623L 21FLPOLKHANCOCK H-4 8/22/2002 750 0.50 32223 16.0 

1623L 21FLPOLKHANCOCK H-52 8/22/2002 930 0.50 32223 134.2 

1623L 21FLPOLKHANCOCK H-59 8/22/2002 945 0.50 32223 144.2 

1623L 21FLPOLKHANCOCK H-62 8/22/2002 1000 0.50 32223 136.8 A 

1623L 21FLTPA 25020276 2/4/2003 940 0.20 32209 57.0 Q 

1623L 21FLTPA 25020276 4/22/2003 1110 0.20 32209 230.0 

1623L 21FLTPA 25020276 8/18/2003 900 0.20 32209 85.0 

1623L 21FLTPA 25020276 11/3/2003 1040 0.20 32209 210.0 

1623L 21FLPOLKHANCOCK H-11 2/19/2004 1120 0.50 32210 146.4 

1623L 21FLPOLKHANCOCK H-22 2/19/2004 1055 0.50 32210 143.7 

1623L 21FLPOLKHANCOCK H-24 2/19/2004 1110 0.50 32210 137.8 

1623L 21FLPOLKHANCOCK H-30 2/19/2004 1045 0.50 32210 156.6 

1623L 21FLPOLKHANCOCK H-33 2/19/2004 950 0.50 32210 175.5 

1623L 21FLPOLKHANCOCK H-34 2/19/2004 1000 0.50 32210 143.1 

1623L 21FLPOLKHANCOCK H-36 2/19/2004 920 0.50 32210 148.0 

1623L 21FLPOLKHANCOCK H-37 2/19/2004 935 0.50 32210 168.6 

1623L 21FLPOLKHANCOCK H-44 2/19/2004 905 0.50 32210 148.0 

1623L 21FLPOLKHANCOCK H-59 2/19/2004 850 0.50 32210 170.1 

1623L 21FLPOLKHANCOCK H-62 2/19/2004 830 0.50 32210 134.3 

1623L 21FLPOLKHANCOCK H-9 2/19/2004 1130 0.50 32210 213.7 

1623L 21FLPOLKHANCOCK H-12 5/5/2004 950 0.50 32210 171.5 

1623L 21FLPOLKHANCOCK H-22 5/5/2004 925 0.40 32210 364.5 

1623L 21FLPOLKHANCOCK H-3 5/5/2004 940 0.40 32210 349.7 

1623L 21FLPOLKHANCOCK H-31 5/5/2004 835 0.50 32210 343.4 

1623L 21FLPOLKHANCOCK H-33 5/5/2004 825 0.50 32210 289.8 

1623L 21FLPOLKHANCOCK H-36 5/5/2004 915 0.50 32210 360.7 

1623L 21FLPOLKHANCOCK H-40 5/5/2004 815 0.50 32210 333.7 

1623L 21FLPOLKHANCOCK H-43 5/5/2004 910 0.50 32210 346.9 

1623L 21FLPOLKHANCOCK H-47 5/5/2004 805 0.50 32210 346.2 

1623L 21FLPOLKHANCOCK H-50 5/5/2004 900 0.50 32210 362.3 

1623L 21FLPOLKHANCOCK H-54 5/5/2004 755 0.50 32210 312.8 

1623L 21FLPOLKHANCOCK H-62 5/5/2004 745 0.50 32210 327.3 

A: Value reported is the mean of two or more determinations. 

E: Extra sample taken in compositing process. 

Q: Sample held beyond normal holding time. 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 92

Lake Hancock Dissolved Oxygen Data 

WBID Station Date Time Depth

Storet 

Code 

DO

(mg/L) R-Code 

1623L 21FLPOLKHANCOCK1 4/9/1992 1141 0.50 299 10.60 

1623L 21FLPOLKHANCOCK1 10/7/1992 1527 0.70 299 2.50 

1623L 21FLPOLKHANCOCK1 3/31/1993 1530 0.70 299 0.90 

1623L 21FLPOLKHANCOCK1 10/7/1993 1107 0.70 299 7.10 

1623L 21FLPOLKHANCOCK1 12/6/1993 1053 0.70 299 11.70 

1623L 21FLPOLKHANCOCK1 12/20/1993 1043 0.70 299 12.50 

1623L 21FLPOLKHANCOCK1 4/12/1994 1210 0.60 299 9.30 

1623L 21FLPOLKHANCOCK1 10/5/1994 1205 0.90 299 8.60 

1623L 21FLPOLKHANCOCK1 4/5/1995 1230 0.80 299 11.50 

1623L 21FLPOLKHANCOCK1 11/8/1995 844 0.80 299 7.30 

1623L 21FLPOLKHANCOCK1 5/8/1996 1200 0.80 299 7.90 

1623L 21FLSWFDSTA0192 8/1/1996 1535 0.50 299 6.10 

1623L 21FLPOLKHANCOCK1 11/13/1996 1248 0.80 299 11.30 

1623L 21FLSWFDSTA0192 1/13/1997 1500 0.50 299 12.23 

1623L 21FLPOLKHANCOCK1 5/7/1997 1150 0.10 299 15.70 

1623L 21FLPOLKHANCOCK1 10/30/1997 1145 0.70 299 10.95 

1623L 21FLPOLKHANCOCK1 5/7/1998 1245 0.80 299 11.56 

1623L 21FLPOLKHANCOCK1 11/9/1998 1015 0.60 299 11.92 

1623L 21FLPOLKHANCOCK1 5/11/1999 900 0.50 299 4.39 

1623L 21FLTPA 25020275 9/7/1999 1110 0.30 299 7.98 

1623L 21FLTPA 25020276 9/7/1999 145 0.30 299 9.25 

1623L 21FLTPA 25020278 9/8/1999 1115 0.60 299 7.98 

1623L 21FLTPA 25020277 9/8/1999 140 0.60 299 10.30 

1623L 21FLPOLKHANCOCK1 11/9/1999 830 0.49 299 9.05 

1623L 21FLPOLKHANCOCK1 5/3/2000 815 0.30 299 0.84 

1623L 21FLPOLKHANCOCK1 11/16/2000 1200 0.40 299 10.08 

1623L 21FLPOLKHANCOCK1 11/20/2001 1400 0.50 299 12.95 

1623L 21FLPOLKHANCOCK B 1/16/2002 915 0.50 299 2.21 

1623L 21FLPOLKHANCOCK C 1/16/2002 945 0.50 299 7.56 

1623L 21FLPOLKHANCOCK A 1/16/2002 845 0.50 299 11.32 

1623L 21FLPOLKHANCOCK D 1/16/2002 1005 0.50 299 12.57 

1623L 21FLPOLKHANCOCK B 2/5/2002 1410 0.50 299 7.29 

1623L 21FLPOLKHANCOCK C 2/5/2002 1435 0.50 299 12.60 

1623L 21FLPOLKHANCOCK A 2/5/2002 1345 0.50 299 13.17 

1623L 21FLPOLKHANCOCK D 2/5/2002 1500 0.50 299 14.45 

1623L 21FLPOLKHANCOCK B 3/7/2002 1400 0.50 299 1.51 

1623L 21FLPOLKHANCOCK D 3/7/2002 1430 0.50 299 1.52 

1623L 21FLPOLKHANCOCK A 3/7/2002 1355 0.50 299 4.79 

1623L 21FLPOLKHANCOCK C 3/7/2002 1416 0.50 299 11.77 

1623L 21FLPOLKHANCOCK H-4 8/22/2002 750 0.50 299 0.38 

1623L 21FLPOLKHANCOCK H-2 8/22/2002 805 0.50 299 3.08 

1623L 21FLPOLKHANCOCK H-23 8/22/2002 845 0.50 299 4.36 

1623L 21FLPOLKHANCOCK H-10 8/22/2002 810 0.50 299 4.43 

1623L 21FLPOLKHANCOCK H-62 8/22/2002 1000 0.50 299 4.94 

1623L 21FLPOLKHANCOCK H-52 8/22/2002 930 0.50 299 5.42 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 93

WBID Station Date Time Depth

Storet 

Code 

DO

(mg/L) R-Code 

1623L 21FLPOLKHANCOCK H-52 8/22/2002 935 0.50 299 5.42 

1623L 21FLPOLKHANCOCK H-37 8/22/2002 855 0.50 299 6.19 

1623L 21FLPOLKHANCOCK H-16 8/22/2002 840 0.50 299 6.51 

1623L 21FLPOLKHANCOCK H-17 8/22/2002 820 0.50 299 7.47 

1623L 21FLPOLKHANCOCK H-59 8/22/2002 945 0.50 299 7.86 

1623L 21FLPOLKHANCOCK H-18 8/22/2002 830 0.50 299 8.14 

1623L 21FLPOLKHANCOCK H-26 8/22/2002 920 0.50 299 8.28 

1623L 21FLPOLKHANCOCK H-40 11/18/2002 1130 0.40 299 1.67 

1623L 21FLPOLKHANCOCK H-2 11/18/2002 925 0.40 299 4.54 

1623L 21FLPOLKHANCOCK H-16 11/18/2002 945 0.20 299 7.69 

1623L 21FLPOLKHANCOCK H-12 11/18/2002 1305 0.50 299 8.41 

1623L 21FLPOLKHANCOCK H-23 11/18/2002 1005 0.50 299 9.12 

1623L 21FLPOLKHANCOCK H-30 11/18/2002 1020 0.50 299 9.44 

1623L 21FLPOLKHANCOCK H-55 11/18/2002 1210 0.40 299 9.64 

1623L 21FLPOLKHANCOCK H-36 11/18/2002 1035 0.40 299 9.98 

1623L 21FLPOLKHANCOCK H-19 11/18/2002 1255 0.50 299 11.04 

1623L 21FLPOLKHANCOCK H-25 11/18/2002 1240 0.40 299 11.38 

1623L 21FLPOLKHANCOCK H-33 11/18/2002 1150 0.50 299 11.84 

1623L 21FLPOLKHANCOCK H-53 11/18/2002 1225 0.50 299 12.11 

1623L 21FLTPA 25020276 2/4/2003 940 0.20 299 5.44 D 

1623L 21FLPOLKHANCOCK H-41 2/13/2003 1040 0.50 299 2.88 

1623L 21FLPOLKHANCOCK H-16 2/13/2003 825 0.50 299 7.63 

1623L 21FLPOLKHANCOCK H-47 2/13/2003 1055 0.50 299 9.01 

1623L 21FLPOLKHANCOCK H-36 2/13/2003 935 0.45 299 10.68 

1623L 21FLPOLKHANCOCK H-22 2/13/2003 915 0.45 299 11.31 

1623L 21FLPOLKHANCOCK H-25 2/13/2003 900 0.50 299 11.93 

1623L 21FLPOLKHANCOCK H-17 2/13/2003 840 0.50 299 12.44 

1623L 21FLPOLKHANCOCK H-29 2/13/2003 920 0.50 299 12.60 

1623L 21FLPOLKHANCOCK H-62 2/13/2003 1140 0.50 299 12.63 

1623L 21FLPOLKHANCOCK H-30 2/13/2003 945 0.50 299 12.69 

1623L 21FLPOLKHANCOCK H-59 2/13/2003 1120 0.50 299 13.09 

1623L 21FLPOLKHANCOCK H-45 2/13/2003 1110 0.50 299 13.58 

1623L 21FLTPA 25020276 4/22/2003 1110 0.20 299 3.94 D 

1623L 21FLPOLKHANCOCK H-4 5/20/2003 1115 0.50 299 2.59 

1623L 21FLPOLKHANCOCK H-56 5/20/2003 920 0.40 299 2.86 

1623L 21FLPOLKHANCOCK H-47 5/20/2003 900 0.50 299 4.37 

1623L 21FLPOLKHANCOCK H-52 5/20/2003 950 0.50 299 5.21 

1623L 21FLPOLKHANCOCK H-38 5/20/2003 1000 0.50 299 5.65 

1623L 21FLPOLKHANCOCK H-37 5/20/2003 1010 0.50 299 5.68 

1623L 21FLPOLKHANCOCK H-40 5/20/2003 845 0.50 299 5.98 

1623L 21FLPOLKHANCOCK H-53 5/20/2003 940 0.50 299 6.46 

1623L 21FLPOLKHANCOCK H-24 5/20/2003 1150 0.50 299 8.07 

1623L 21FLPOLKHANCOCK H-25 5/20/2003 1140 0.50 299 8.12 

1623L 21FLPOLKHANCOCK H-32 5/20/2003 1210 0.50 299 8.37 

1623L 21FLPOLKHANCOCK H-31 5/20/2003 1200 0.50 299 8.43 

1623L 21FLTPA 25020276 8/18/2003 900 0.20 299 6.40 

1623L 21FLPOLKHANCOCK H-4 8/20/2003 820 0.50 299 1.77 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 94

WBID Station Date Time Depth

Storet 

Code 

DO

(mg/L) R-Code 

1623L 21FLPOLKHANCOCK H-23 8/20/2003 855 0.50 299 3.89 

1623L 21FLPOLKHANCOCK H-24 8/20/2003 850 0.50 299 4.38 

1623L 21FLPOLKHANCOCK H-37 8/20/2003 910 0.50 299 4.96 

1623L 21FLPOLKHANCOCK H-18 8/20/2003 840 0.50 299 5.19 

1623L 21FLPOLKHANCOCK H-39 8/20/2003 930 0.50 299 5.46 

1623L 21FLPOLKHANCOCK H-38 8/20/2003 920 0.50 299 5.61 

1623L 21FLPOLKHANCOCK H-47 8/20/2003 1050 0.50 299 5.92 

1623L 21FLPOLKHANCOCK H-61 8/20/2003 1025 0.50 299 6.07 

1623L 21FLPOLKHANCOCK H-51 8/20/2003 1000 0.50 299 6.36 

1623L 21FLPOLKHANCOCK H-59 8/20/2003 1015 0.50 299 8.42 

1623L 21FLPOLKHANCOCK H-48 8/20/2003 1040 0.50 299 8.45 

1623L 21FLTPA 25020276 11/3/2003 1040 0.20 299 4.76 

1623L 21FLPOLKHANCOCK H-49 11/18/2003 920 0.50 299 2.77 

1623L 21FLPOLKHANCOCK H-16 11/18/2003 1130 0.50 299 7.04 

1623L 21FLPOLKHANCOCK H-22 11/18/2003 1120 0.50 299 9.12 

1623L 21FLPOLKHANCOCK H-30 11/18/2003 1110 0.50 299 9.12 

1623L 21FLPOLKHANCOCK H-34 11/18/2003 945 0.50 299 9.38 

1623L 21FLPOLKHANCOCK H-40 11/18/2003 955 0.50 299 9.59 

1623L 21FLPOLKHANCOCK H-31 11/18/2003 1100 0.50 299 10.00 

1623L 21FLPOLKHANCOCK H-48 11/18/2003 905 0.50 299 10.36 

1623L 21FLPOLKHANCOCK H-54 11/18/2003 850 0.50 299 10.74 

1623L 21FLPOLKHANCOCK H-43 11/18/2003 1010 0.50 299 10.81 

1623L 21FLPOLKHANCOCK H-3 11/18/2003 1140 0.50 299 10.85 

1623L 21FLPOLKHANCOCK H-11 11/18/2003 1150 0.50 299 11.78 

1623L 21FLPOLKHANCOCK H-36 2/19/2004 920 0.50 299 9.84 

1623L 21FLPOLKHANCOCK H-22 2/19/2004 1055 0.50 299 10.14 

1623L 21FLPOLKHANCOCK H-62 2/19/2004 830 0.50 299 10.57 

1623L 21FLPOLKHANCOCK H-44 2/19/2004 905 0.50 299 10.67 

1623L 21FLPOLKHANCOCK H-59 2/19/2004 850 0.50 299 10.93 

1623L 21FLPOLKHANCOCK H-37 2/19/2004 935 0.50 299 10.95 

1623L 21FLPOLKHANCOCK H-34 2/19/2004 1000 0.50 299 11.34 

1623L 21FLPOLKHANCOCK H-24 2/19/2004 1110 0.50 299 11.87 

1623L 21FLPOLKHANCOCK H-9 2/19/2004 1130 0.50 299 11.89 

1623L 21FLPOLKHANCOCK H-33 2/19/2004 950 0.50 299 11.94 

1623L 21FLPOLKHANCOCK H-30 2/19/2004 1045 0.50 299 12.83 

1623L 21FLPOLKHANCOCK H-11 2/19/2004 1120 0.50 299 14.06 

1623L 21FLPOLKHANCOCK H-12 5/5/2004 950 0.50 299 4.65 

1623L 21FLPOLKHANCOCK H-36 5/5/2004 915 0.50 299 7.12 

1623L 21FLPOLKHANCOCK H-47 5/5/2004 805 0.50 299 7.66 

1623L 21FLPOLKHANCOCK H-50 5/5/2004 900 0.50 299 7.69 

1623L 21FLPOLKHANCOCK H-43 5/5/2004 910 0.50 299 7.90 

1623L 21FLPOLKHANCOCK H-40 5/5/2004 815 0.50 299 8.39 

1623L 21FLPOLKHANCOCK H-62 5/5/2004 745 0.50 299 8.43 

1623L 21FLPOLKHANCOCK H-3 5/5/2004 940 0.40 299 8.49 

1623L 21FLPOLKHANCOCK H-33 5/5/2004 825 0.50 299 8.49 

1623L 21FLPOLKHANCOCK H-31 5/5/2004 835 0.50 299 8.79 

1623L 21FLPOLKHANCOCK H-54 5/5/2004 755 0.50 299 8.99 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 95

WBID Station Date Time Depth

Storet 

Code 

DO

(mg/L) R-Code 

1623L 21FLPOLKHANCOCK H-22 5/5/2004 925 0.40 299 9.03 

D: Field measurement. 

Lower Saddle Creek TN Data 

WBID Station Date Time Depth

Storet 

Code 

TN 

(mg/L) R-Code 

1623K 21FLSWFDFLO0038 3/26/1992 1200 8.00 600 2.46 

1623K 21FLSWFDFLO0038 7/8/1992 1005 2.00 600 11.02 

1623K 112WRD 02294491 8/21/1992 1035 0.50 600 6.42 

1623K 21FLSWFDFLO0038 9/22/1992 1420 4.10 600 3.22 

1623K 112WRD 02294491 10/29/1992 1645 0.50 600 5.40 

1623K 21FLSWFDFLO0038 12/7/1992 1500 2.00 600 2.22 

1623K 21FLPOLKP.C. CANAL9 2/11/1993 1250 0.50 600 3.43 

1623K 21FLPOLKP.C. CANAL9 5/13/1993 910 0.20 600 4.24 

1623K 21FLPOLKP.C. CANAL9 8/17/1993 1320 0.30 600 5.11 

1623K 21FLPOLKP.C. CANAL9 11/23/1993 910 0.40 600 3.42 

1623K 112WRD 02294491 2/9/1994 1015 0.50 600 3.72 

1623K 112WRD 02294491 7/14/1994 1000 0.50 600 8.22 

1623K 112WRD 02294491 8/9/1994 1610 0.50 600 6.42 

1623K 112WRD 02294491 8/23/1994 1020 0.50 600 5.32 

1623K 21FLPOLKP.C. CANAL9 8/16/1995 1153 0.60 600 1.49 

1623K 21FLPOLKP.C. CANAL9 11/21/1995 915 0.50 600 2.55 

1623K 21FLPOLKP.C. CANAL9 2/7/1996 928 0.50 600 2.15 

1623K 21FLPOLKP.C. CANAL9 5/21/1996 815 0.50 600 5.10 

1623K 21FLPOLKP.C. CANAL9 8/14/1996 835 0.50 600 4.59 

1623K 21FLPOLKP.C. CANAL9 11/20/1996 825 0.50 600 1.78 

1623K 21FLPOLKP.C. CANAL9 2/12/1997 825 0.50 600 4.22 

1623K 21FLPOLKP.C. CANAL9 5/20/1997 830 0.50 600 2.67 

1623K 21FLPOLKP.C. CANAL9 8/12/1997 925 0.80 600 2.33 

1623K 21FLPOLKP.C. CANAL9 11/5/1997 1112 0.70 600 4.31 

1623K 21FLPOLKP.C. CANAL9 5/13/1998 1040 0.80 600 3.23 

1623K 21FLPOLKP.C. CANAL9 8/10/1998 1100 0.70 600 2.45 

1623K 21FLSWFDFLO 37 72 0 10/7/1998 900 0.30 600 0.89 

1623K 21FLSWFDFLO 37 72 0 11/9/1998 1115 0.30 600 1.20 

1623K 21FLPOLKP.C. CANAL9 11/12/1998 1050 0.50 600 4.83 

1623K 21FLSWFDFLO 37 72 0 12/17/1998 1130 0.30 600 0.39 

1623K 21FLSWFDFLO 37 72 0 1/5/1999 1615 0.30 600 1.30 

1623K 21FLSWFDFLO 37 72 0 1/7/1999 1355 0.50 600 0.59 

1623K 21FLPOLKP.C. CANAL9 2/1/1999 1030 0.25 600 2.49 

1623K 21FLSWFDFLO 37 72 0 2/9/1999 1200 0.80 600 0.73 

1623K 21FLSWFDFLO 37 72 0 3/1/1999 1650 0.50 600 1.70 

1623K 21FLSWFDFLO 37 72 0 3/24/1999 1135 0.50 600 0.88 

1623K 21FLSWFDFLO 37 72 0 4/5/1999 1030 0.80 600 1.50 

1623K 21FLSWFDFLO 37 72 0 4/6/1999 1245 0.50 600 1.20 

1623K 21FLPOLKP.C. CANAL9 4/14/1999 851 0.50 600 2.54 

1623K 21FLSWFDFLO 37 72 0 5/10/1999 1445 0.65 600 1.00 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 96

WBID Station Date Time Depth

Storet 

Code 

TN 

(mg/L) R-Code 

1623K 21FLSWFDFLO 37 72 0 6/9/1999 1000 0.75 600 1.30 

1623K 21FLPOLKP.C. CANAL9 7/14/1999 940 0.50 600 2.66 

1623K 21FLSWFDFLO 37 72 0 7/17/1999 925 0.30 600 1.30 

1623K 21FLSWFDFLO 37 72 0 8/16/1999 1030 0.50 600 1.00 

1623K 21FLSWFDFLO 37 72 0 9/16/1999 1040 0.50 600 1.90 

1623K 21FLSWFDFLO 37 72 0 10/4/1999 1410 0.50 600 1.10 

1623K 21FLPOLKP.C. CANAL9 1/13/2000 950 0.50 600 1.82 

1623K 21FLPOLKP.C. CANAL9 4/17/2000 900 0.50 600 5.05 

1623K 21FLSWFDFLO 37 72 0 5/3/2000 1100 0.50 600 1.15 

1623K 21FLPOLKP.C. CANAL9 7/18/2000 710 0.30 600 1.92 

1623K 21FLPOLKP.C. CANAL9 10/5/2000 1000 0.50 600 2.65 

1623K 21FLPOLKP.C. CANAL9 1/9/2001 1245 0.20 600 1.04 

1623K 21FLPOLKP.C. CANAL9 3/6/2001 1100 0.30 600 1.26 

1623K 21FLPOLKP.C. CANAL9 10/29/2001 1330 0.50 600 2.11 

1623K 21FLSWFDFLO 37 72 0 12/10/2001 1020 0.50 600 2.31 

1623K 21FLSWFDFLO 37 72 0 1/8/2002 1035 0.50 600 2.26 

1623K 21FLPOLKP.C. CANAL9 1/15/2002 1145 0.33 600 1.99 

1623K 21FLSWFDFLO 37 72 0 2/6/2002 915 0.50 600 2.27 

1623K 21FLSWFDFLO 37 72 0 3/4/2002 1110 0.50 600 2.34 

1623K 21FLSWFDFLO 37 72 0 4/2/2002 1115 0.50 600 2.59 

1623K 21FLPOLKP.C. CANAL9 4/17/2002 1055 0.15 600 1.54 

1623K 21FLSWFDFLO 37 72 0 5/6/2002 1050 0.50 600 3.24 

1623K 21FLSWFDFLO 37 72 0 7/4/2002 1530 0.50 600 2.50 

1623K 21FLPOLKP.C. CANAL9 7/24/2002 930 0.50 600 4.36 

1623K 21FLSWFDFLO 37 72 0 9/5/2002 1700 0.50 600 3.13 

1623K 21FLSWFDFLO 37 72 0 10/1/2002 1200 0.50 600 3.19 

1623K 21FLPOLKP.C. CANAL9 10/23/2002 930 0.30 600 3.60 

1623K 21FLSWFDFLO 37 72 0 11/4/2002 1040 0.50 600 3.11 

1623K 21FLSWFDFLO 37 72 0 12/4/2002 1050 0.50 600 3.16 

1623K 21FLPOLKP.C. CANAL9 1/28/2003 1005 0.50 600 2.07 

1623K 21FLPOLKP.C. CANAL9 4/16/2003 930 0.50 600 4.58 

1623K 21FLPOLKP.C. CANAL9 7/23/2003 915 0.50 600 6.42 

1623K 21FLPOLKP.C. CANAL9 10/8/2003 1020 0.50 600 2.74 

1623K 21FLPOLKP.C. CANAL9 1/7/2004 940 0.40 600 4.11 

1623K 21FLPOLKP.C. CANAL9 4/15/2004 955 0.25 600 5.03 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 97

Lower Saddle Creek TP Data 

WBID Station Date Time Depth

Storet 

Code 

TP 

(mg/L) R-Code 

1623K 21FLSWFDFLO0038 3/26/1992 1200 8.00 665 0.07 

1623K 21FLSWFDFLO0038 7/8/1992 1005 2.00 665 0.88 

1623K 112WRD 02294491 8/21/1992 1035 0.50 665 0.42 

1623K 21FLSWFDFLO0038 9/22/1992 1420 4.10 665 0.26 

1623K 112WRD 02294491 9/25/1992 1130 0.50 665 0.17 

1623K 112WRD 02294491 10/29/1992 1645 0.50 665 0.76 

1623K 21FLSWFDFLO0038 12/7/1992 1500 2.00 665 0.42 

1623K 21FLPOLKP.C. CANAL9 2/11/1993 1250 0.50 665 0.28 

1623K 112WRD 02294491 4/16/1993 1150 0.50 665 0.47 

1623K 21FLPOLKP.C. CANAL9 5/13/1993 910 0.20 665 0.73 

1623K 112WRD 02294491 7/9/1993 1300 0.50 665 1.10 

1623K 21FLPOLKP.C. CANAL9 8/17/1993 1320 0.30 665 0.63 

1623K 112WRD 02294491 9/23/1993 1130 0.50 665 0.35 

1623K 112WRD 02294491 10/13/1993 1300 0.50 665 0.30 

1623K 21FLPOLKP.C. CANAL9 11/23/1993 910 0.40 665 1.17 

1623K 112WRD 02294491 2/9/1994 1015 0.50 665 0.24 

1623K 112WRD 02294491 7/14/1994 1000 0.50 665 0.20 

1623K 112WRD 02294491 8/9/1994 1610 0.50 665 0.15 

1623K 112WRD 02294491 8/23/1994 1020 0.50 665 0.33 

1623K 21FLPOLKP.C. CANAL9 8/16/1995 1153 0.60 665 0.40 

1623K 21FLPOLKP.C. CANAL9 11/21/1995 915 0.50 665 0.58 

1623K 21FLPOLKP.C. CANAL9 2/7/1996 928 0.33 665 0.30 

1623K 21FLPOLKP.C. CANAL9 5/21/1996 815 0.33 665 0.62 

1623K 21FLPOLKP.C. CANAL9 8/14/1996 835 0.33 665 0.65 

1623K 21FLPOLKP.C. CANAL9 11/20/1996 825 0.33 665 0.38 

1623K 21FLPOLKP.C. CANAL9 2/12/1997 825 0.50 665 0.30 

1623K 21FLPOLKP.C. CANAL9 5/20/1997 830 0.50 665 0.58 

1623K 21FLSWFDFLO 37 72 0 8/4/1997 1200 1.00 665 0.39 

1623K 21FLPOLKP.C. CANAL9 8/12/1997 925 0.80 665 0.21 

1623K 21FLSWFDFLO 37 72 0 9/10/1997 1030 1.00 665 0.15 

1623K 21FLSWFDFLO 37 72 0 10/6/1997 1130 1.00 665 0.39 

1623K 21FLSWFDFLO 37 72 0 11/3/1997 1040 0.30 665 0.45 

1623K 21FLPOLKP.C. CANAL9 11/5/1997 1112 0.70 665 0.35 

1623K 21FLSWFDFLO 37 72 0 1/22/1998 1330 0.50 665 0.03 

1623K 21FLSWFDFLO 37 72 0 2/2/1998 1040 0.70 665 0.55 

1623K 21FLPOLKP.C. CANAL9 2/10/1998 1130 1.40 665 0.60 

1623K 21FLSWFDFLO 37 72 0 3/2/1998 1015 0.30 665 0.65 

1623K 21FLSWFDFLO 37 72 0 3/26/1998 1030 0.50 665 0.02 

1623K 21FLSWFDFLO 37 72 0 4/6/1998 1010 0.30 665 0.51 

1623K 21FLSWFDFLO 37 72 0 4/15/1998 1125 0.50 665 0.03 

1623K 21FLSWFDFLO 37 72 0 5/4/1998 1215 0.30 665 0.60 

1623K 21FLPOLKP.C. CANAL9 5/13/1998 1040 0.80 665 0.57 

1623K 21FLSWFDFLO 37 72 0 5/15/1998 1100 0.50 665 0.04 

1623K 21FLSWFDFLO 37 72 0 6/1/1998 1045 0.30 665 0.40 

1623K 21FLSWFDFLO 37 72 0 6/16/1998 1345 0.50 665 0.02 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 98

WBID Station Date Time Depth

Storet 

Code 

TP 

(mg/L) R-Code 

1623K 21FLSWFDFLO 37 72 0 7/6/1998 1100 0.30 665 0.71 

1623K 21FLSWFDFLO 37 72 0 7/28/1998 1230 0.50 665 0.02 

1623K 21FLSWFDFLO 37 72 0 8/3/1998 1130 0.60 665 0.58 

1623K 21FLPOLKP.C. CANAL9 8/10/1998 1100 0.70 665 0.47 

1623K 21FLSWFDFLO 37 72 0 8/11/1998 1230 0.50 665 0.03 

1623K 21FLSWFDFLO 37 72 0 9/8/1998 1015 0.30 665 0.60 

1623K 21FLSWFDFLO 37 72 0 9/10/1998 1245 0.50 665 0.01 

1623K 21FLSWFDFLO 37 72 0 10/7/1998 900 0.30 665 0.31 

1623K 21FLSWFDFLO 37 72 0 10/12/1998 1545 0.50 665 0.03 

1623K 21FLSWFDFLO 37 72 0 11/9/1998 1115 0.30 665 0.29 

1623K 21FLPOLKP.C. CANAL9 11/12/1998 1050 0.50 665 0.66 

1623K 21FLSWFDFLO 37 72 0 12/9/1998 1355 0.50 665 0.02 

1623K 21FLSWFDFLO 37 72 0 12/17/1998 1130 0.30 665 0.24 

1623K 21FLSWFDFLO 37 72 0 1/5/1999 1615 0.30 665 0.33 

1623K 21FLSWFDFLO 37 72 0 1/7/1999 1355 . 665 0.03 

1623K 21FLPOLKP.C. CANAL9 2/1/1999 1030 0.25 665 0.44 

1623K 21FLSWFDFLO 37 72 0 2/9/1999 1200 0.80 665 0.28 

1623K 21FLSWFDFLO 37 72 0 3/1/1999 1650 0.50 665 0.15 

1623K 21FLSWFDFLO 37 72 0 3/24/1999 1135 0.50 665 0.03 

1623K 21FLSWFDFLO 37 72 0 4/5/1999 1030 0.80 665 0.31 

1623K 21FLSWFDFLO 37 72 0 4/6/1999 1245 0.50 665 0.02 

1623K 21FLPOLKP.C. CANAL9 4/14/1999 851 0.50 665 0.72 

1623K 21FLSWFDFLO 37 72 0 5/10/1999 1445 0.65 665 0.44 

1623K 21FLSWFDFLO 37 72 0 6/9/1999 1000 0.75 665 0.50 

1623K 21FLPOLKP.C. CANAL9 7/14/1999 940 0.50 665 0.33 

1623K 21FLSWFDFLO 37 72 0 7/17/1999 925 0.30 665 0.16 

1623K 21FLSWFDFLO 37 72 0 8/16/1999 1030 0.50 665 0.18 

1623K 21FLSWFDFLO 37 72 0 9/16/1999 1040 0.50 665 0.56 

1623K 21FLSWFDFLO 37 72 0 10/4/1999 1410 0.50 665 0.18 

1623K 21FLPOLKP.C. CANAL9 10/5/1999 950 1.63 665 0.37 

1623K 21FLSWFDFLO 37 72 0 11/1/1999 930 0.50 665 0.05 

1623K 21FLSWFDFLO 37 72 0 12/8/1999 1000 0.50 665 0.10 

1623K 21FLSWFDFLO 37 72 0 1/5/2000 1030 0.50 665 0.16 

1623K 21FLPOLKP.C. CANAL9 1/13/2000 950 0.50 665 0.15 

1623K 21FLSWFDFLO 37 72 0 2/8/2000 1130 0.50 665 0.33 

1623K 21FLSWFDFLO 37 72 0 3/15/2000 1100 0.50 665 0.21 

1623K 21FLPOLKP.C. CANAL9 4/17/2000 900 0.50 665 0.69 

1623K 21FLSWFDFLO 37 72 0 5/3/2000 1100 0.50 665 0.07 

1623K 21FLSWFDFLO 37 72 0 5/11/2000 1000 0.50 665 0.64 

1623K 21FLSWFDFLO 37 72 0 6/6/2000 1155 0.50 665 0.03 

1623K 21FLSWFDFLO 37 72 0 6/8/2000 1100 0.50 665 0.96 

1623K 21FLSWFDFLO 37 72 0 7/6/2000 1445 0.50 665 0.40 

1623K 21FLPOLKP.C. CANAL9 7/18/2000 710 0.30 665 0.86 

1623K 21FLSWFDFLO 37 72 0 8/1/2000 1145 0.50 665 0.03 

1623K 21FLSWFDFLO 37 72 0 8/8/2000 1500 0.50 665 0.33 

1623K 21FLSWFDFLO 37 72 0 9/12/2000 1000 0.50 665 0.52 

1623K 21FLSWFDFLO 37 72 0 9/13/2000 1145 0.50 665 0.04 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 99

WBID Station Date Time Depth

Storet 

Code 

TP 

(mg/L) R-Code 

1623K 21FLSWFDFLO 37 72 0 10/3/2000 1510 0.50 665 0.39 

1623K 21FLPOLKP.C. CANAL9 10/5/2000 1000 0.50 665 1.90 

1623K 21FLSWFDFLO 37 72 0 10/17/2000 1530 0.50 665 0.03 

1623K 21FLSWFDFLO 37 72 0 11/1/2000 1120 0.50 665 0.02 

1623K 21FLSWFDFLO 37 72 0 11/6/2000 1430 0.50 665 1.96 

1623K 21FLSWFDFLO 37 72 0 12/6/2000 1330 0.50 665 1.27 

1623K 21FLPOLKP.C. CANAL9 1/9/2001 1245 0.20 665 0.35 

1623K 21FLSWFDFLO 37 72 0 2/7/2001 1545 0.55 665 3.21 

1623K 21FLPOLKP.C. CANAL9 3/6/2001 1100 0.30 665 0.62 

1623K 21FLSWFDFLO 37 72 0 3/7/2001 945 0.50 665 2.95 

1623K 21FLSWFDFLO 37 72 0 4/3/2001 1015 0.50 665 1.42 

1623K 21FLSWFDFLO 37 72 0 5/9/2001 1040 0.50 665 1.20 

1623K 21FLSWFDFLO 37 72 0 6/5/2001 940 0.32 665 1.38 

1623K 21FLSWFDFLO 37 72 0 8/9/2001 1330 0.50 665 10.50 

1623K 21FLSWFDFLO 37 72 0 9/4/2001 1050 0.50 665 2.17 

1623K 21FLSWFDFLO 37 72 0 10/2/2001 1050 0.50 665 0.72 

1623K 21FLPOLKP.C. CANAL9 10/29/2001 1330 0.50 665 1.01 

1623K 21FLSWFDFLO 37 72 0 12/10/2001 1020 0.50 665 0.88 

1623K 21FLSWFDFLO 37 72 0 1/8/2002 1035 0.50 665 0.92 

1623K 21FLPOLKP.C. CANAL9 1/15/2002 1145 0.33 665 0.53 

1623K 21FLSWFDFLO 37 72 0 2/6/2002 915 0.50 665 0.88 

1623K 21FLSWFDFLO 37 72 0 3/4/2002 1110 0.50 665 0.75 

1623K 21FLSWFDFLO 37 72 0 4/2/2002 1115 0.50 665 0.66 

1623K 21FLPOLKP.C. CANAL9 4/17/2002 1055 0.15 665 1.06 

1623K 21FLSWFDFLO 37 72 0 5/6/2002 1050 0.50 665 0.51 

1623K 21FLSWFDFLO 37 72 0 7/4/2002 1530 0.50 665 0.92 

1623K 21FLPOLKP.C. CANAL9 7/24/2002 930 0.50 665 0.61 

1623K 21FLSWFDFLO 37 72 0 9/5/2002 1700 0.50 665 0.80 

1623K 21FLSWFDFLO 37 72 0 10/1/2002 1200 0.50 665 0.38 

1623K 21FLPOLKP.C. CANAL9 10/23/2002 930 0.30 665 0.67 

1623K 21FLSWFDFLO 37 72 0 11/4/2002 1040 0.50 665 0.76 

1623K 21FLSWFDFLO 37 72 0 12/4/2002 1050 0.50 665 0.21 

1623K 21FLPOLKP.C. CANAL9 1/28/2003 1005 0.50 665 0.53 

1623K 21FLTPA 27552158149358 2/5/2003 1345 0.20 665 0.73 

1623K 21FLPOLKP.C. CANAL9 4/16/2003 930 0.50 665 1.01 

1623K 21FLTPA 27552158149358 4/22/2003 1000 0.20 665 1.10 

1623K 21FLPOLKP.C. CANAL9 7/23/2003 915 0.50 665 0.97 

1623K 21FLTPA 27552158149358 8/19/2003 950 0.20 665 0.66 

1623K 21FLPOLKP.C. CANAL9 10/8/2003 1020 0.50 665 0.85 

1623K 21FLTPA 27552158149358 11/4/2003 1145 0.20 665 0.78 

1623K 21FLPOLKP.C. CANAL9 1/7/2004 940 0.40 665 1.04 

1623K 21FLPOLKP.C. CANAL9 4/15/2004 955 0.25 665 1.23 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 100

Lower Saddle Creek Chlorophyll a Data 

WBID Station Date Time Depth

Storet 

Code 

Chla

(μg/L) R-Code 

1623K 21FLPOLKP.C. CANAL9 8/16/1995 1153 1.97 32210 118.2 

1623K 21FLPOLKP.C. CANAL9 11/21/1995 915 0.33 32210 109.2 

1623K 21FLPOLKP.C. CANAL9 2/7/1996 928 0.33 32210 42.8 

1623K 21FLPOLKP.C. CANAL9 5/21/1996 815 0.33 32210 201.9 

1623K 21FLPOLKP.C. CANAL9 8/14/1996 835 0.33 32210 157.7 

1623K 21FLPOLKP.C. CANAL9 11/20/1996 825 0.33 32210 59.5 

1623K 21FLPOLKP.C. CANAL9 2/12/1997 825 2.95 32210 141.8 

1623K 21FLPOLKP.C. CANAL9 5/20/1997 830 1.31 32210 110.1 

1623K 21FLSWFDFLO 37 72 0 8/4/1997 1200 1.00 32209 114.9 

1623K 21FLPOLKP.C. CANAL9 8/12/1997 925 2.62 32210 71.7 

1623K 21FLSWFDFLO 37 72 0 9/10/1997 1030 1.00 32209 61.4 

1623K 21FLSWFDFLO 37 72 0 10/6/1997 1130 1.00 32209 43.0 

1623K 21FLSWFDFLO 37 72 0 11/3/1997 1040 0.30 32209 112.9 

1623K 21FLPOLKP.C. CANAL9 11/5/1997 1112 2.30 32210 136.0 

1623K 21FLSWFDFLO 37 72 0 12/1/1997 1035 1.40 32210 195.0 

1623K 21FLSWFDFLO 37 72 0 12/1/1997 1035 1.40 32209 96.1 

1623K 21FLSWFDFLO 37 72 0 1/22/1998 1330 0.50 32209 5.3 

1623K 21FLSWFDFLO 37 72 0 2/2/1998 1040 0.70 32209 53.4 

1623K 21FLSWFDFLO 37 72 0 3/2/1998 1015 0.30 32209 229.6 

1623K 21FLSWFDFLO 37 72 0 3/26/1998 1030 0.50 32209 1.6 

1623K 21FLSWFDFLO 37 72 0 4/6/1998 1010 0.30 32209 133.5 

1623K 21FLSWFDFLO 37 72 0 4/15/1998 1125 0.50 32209 1.0 

1623K 21FLSWFDFLO 37 72 0 5/4/1998 1215 0.30 32209 80.1 

1623K 21FLSWFDFLO 37 72 0 5/15/1998 1100 0.50 32209 1.6 

1623K 21FLSWFDFLO 37 72 0 6/1/1998 1045 0.30 32210 166.0 

1623K 21FLSWFDFLO 37 72 0 6/1/1998 1045 0.30 32209 138.8 

1623K 21FLSWFDFLO 37 72 0 6/16/1998 1345 0.50 32209 4.8 

1623K 21FLSWFDFLO 37 72 0 7/6/1998 1100 0.30 32209 267.0 

1623K 21FLSWFDFLO 37 72 0 7/28/1998 1230 0.50 32209 4.3 

1623K 21FLSWFDFLO 37 72 0 8/3/1998 1130 0.60 32209 96.1 

1623K 21FLSWFDFLO 37 72 0 8/11/1998 1230 0.50 32210 5.0 

1623K 21FLSWFDFLO 37 72 0 8/11/1998 1230 0.50 32209 1.0 

1623K 21FLSWFDFLO 37 72 0 9/8/1998 1015 0.30 32209 96.1 

1623K 21FLSWFDFLO 37 72 0 9/10/1998 1245 0.50 32209 3.7 

1623K 21FLSWFDFLO 37 72 0 10/7/1998 900 0.30 32209 93.5 

1623K 21FLSWFDFLO 37 72 0 10/12/1998 1545 0.50 32209 10.7 

1623K 21FLSWFDFLO 37 72 0 11/9/1998 1115 0.30 32209 203.0 

1623K 21FLSWFDFLO 37 72 0 11/9/1998 1320 0.50 32209 3.7 

1623K 21FLSWFDFLO 37 72 0 12/9/1998 1355 0.50 32209 1.6 

1623K 21FLSWFDFLO 37 72 0 12/17/1998 1130 0.30 32209 98.6 

1623K 21FLSWFDFLO 37 72 0 1/5/1999 1615 0.30 32209 223.0 

1623K 21FLSWFDFLO 37 72 0 1/7/1999 1355 0.50 32209 83.5 

1623K 21FLPOLKP.C. CANAL9 2/1/1999 1030 0.25 32223 52.1 

1623K 21FLSWFDFLO 37 72 0 2/9/1999 1200 0.80 32209 79.3 

1623K 21FLSWFDFLO 37 72 0 3/1/1999 1650 0.50 32209 110.0 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 101

WBID Station Date Time Depth

Storet 

Code 

Chla

(μg/L) R-Code 

1623K 21FLSWFDFLO 37 72 0 3/24/1999 1135 0.50 32209 7.4 

1623K 21FLSWFDFLO 37 72 0 4/5/1999 1030 0.80 32209 172.1 

1623K 21FLSWFDFLO 37 72 0 4/6/1999 1245 0.50 32209 31.3 

1623K 21FLPOLKP.C. CANAL9 4/14/1999 851 0.50 32223 52.1 

1623K 21FLSWFDFLO 37 72 0 5/10/1999 1445 0.65 32209 229.0 

1623K 21FLSWFDFLO 37 72 0 6/9/1999 1000 0.75 32209 310.0 

1623K 21FLPOLKP.C. CANAL9 7/14/1999 940 0.50 32223 108.1 

1623K 21FLSWFDFLO 37 72 0 7/17/1999 925 0.30 32209 88.1 

1623K 21FLSWFDFLO 37 72 0 8/16/1999 1030 0.50 32209 115.0 

1623K 21FLSWFDFLO 37 72 0 9/16/1999 1040 0.50 32209 333.0 

1623K 21FLSWFDFLO 37 72 0 10/4/1999 1410 0.50 32209 350.0 

1623K 21FLSWFDFLO 37 72 0 11/1/1999 930 0.50 32209 71.8 

1623K 21FLSWFDFLO 37 72 0 12/8/1999 1000 0.50 32209 63.1 

1623K 21FLSWFDFLO 37 72 0 1/5/2000 1030 0.50 32209 45.4 

1623K 21FLPOLKP.C. CANAL9 1/13/2000 950 0.50 32223 32.0 

1623K 21FLSWFDFLO 37 72 0 2/8/2000 1130 0.50 32209 32.0 

1623K 21FLSWFDFLO 37 72 0 3/15/2000 1100 0.50 32209 13.4 

1623K 21FLPOLKP.C. CANAL9 4/17/2000 900 0.50 32223 100.2 

1623K 21FLSWFDFLO 37 72 0 5/3/2000 1100 0.50 32209 1.0 

1623K 21FLSWFDFLO 37 72 0 5/11/2000 1000 0.50 32209 117.0 

1623K 21FLSWFDFLO 37 72 0 6/6/2000 1155 0.50 32209 1.0 

1623K 21FLSWFDFLO 37 72 0 6/8/2000 1100 0.50 32209 512.0 

1623K 21FLSWFDFLO 37 72 0 7/6/2000 1340 0.50 32209 3.2 

1623K 21FLSWFDFLO 37 72 0 7/6/2000 1445 0.50 32209 66.8 

1623K 21FLPOLKP.C. CANAL9 7/18/2000 710 0.30 32223 32.4 

1623K 21FLSWFDFLO 37 72 0 8/1/2000 1145 0.50 32209 1.1 

1623K 21FLSWFDFLO 37 72 0 8/8/2000 1500 0.50 32209 117.0 

1623K 21FLSWFDFLO 37 72 0 9/12/2000 1000 0.50 32209 21.4 

1623K 21FLSWFDFLO 37 72 0 9/13/2000 1145 0.50 32209 6.4 

1623K 21FLSWFDFLO 37 72 0 10/3/2000 1510 0.50 32209 14.7 

1623K 21FLPOLKP.C. CANAL9 10/5/2000 1000 0.50 32223 1.0 

1623K 21FLSWFDFLO 37 72 0 10/17/2000 1530 0.50 32209 3.6 

1623K 21FLSWFDFLO 37 72 0 11/1/2000 1120 0.50 32209 1.0 

1623K 21FLSWFDFLO 37 72 0 11/6/2000 1430 0.50 32209 363.0 

1623K 21FLSWFDFLO 37 72 0 12/6/2000 1330 0.50 32209 246.0 

1623K 21FLPOLKP.C. CANAL9 1/9/2001 1245 0.20 32223 3.2 

1623K 21FLSWFDFLO 37 72 0 2/7/2001 1545 0.55 32209 612.0 

1623K 21FLPOLKP.C. CANAL9 3/6/2001 1100 0.30 32223 4.0 

1623K 21FLSWFDFLO 37 72 0 3/7/2001 945 0.50 32209 260.0 

1623K 21FLSWFDFLO 37 72 0 4/3/2001 1015 0.50 32209 240.0 

1623K 21FLSWFDFLO 37 72 0 5/9/2001 1040 0.50 32209 58.7 

1623K 21FLSWFDFLO 37 72 0 6/5/2001 940 0.32 32209 62.7 

1623K 21FLSWFDFLO 37 72 0 8/9/2001 1330 0.50 32209 1.0 

1623K 21FLSWFDFLO 37 72 0 9/4/2001 1050 0.50 32209 21.4 

1623K 21FLSWFDFLO 37 72 0 10/2/2001 1050 0.50 32209 17.4 

1623K 21FLPOLKP.C. CANAL9 10/29/2001 1330 0.50 32223 115.3 

1623K 21FLSWFDFLO 37 72 0 12/10/2001 1020 0.50 32209 44.1 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 102

WBID Station Date Time Depth

Storet 

Code 

Chla

(μg/L) R-Code 

1623K 21FLSWFDFLO 37 72 0 1/8/2002 1035 0.50 32209 29.7 

1623K 21FLPOLKP.C. CANAL9 1/15/2002 1145 0.33 32223 40.1 

1623K 21FLSWFDFLO 37 72 0 2/6/2002 915 0.50 32209 36.3 

1623K 21FLSWFDFLO 37 72 0 3/4/2002 1110 0.50 32209 104.7 

1623K 21FLSWFDFLO 37 72 0 4/2/2002 1115 0.50 32209 59.1 

1623K 21FLPOLKP.C. CANAL9 4/17/2002 1055 0.15 32223 24.8 

1623K 21FLSWFDFLO 37 72 0 5/6/2002 1050 0.50 32209 151.0 

1623K 21FLSWFDFLO 37 72 0 7/4/2002 1530 0.50 32209 91.8 

1623K 21FLPOLKP.C. CANAL9 7/24/2002 930 0.50 32223 108.1 

1623K 21FLSWFDFLO 37 72 0 9/5/2002 1700 0.50 32209 120.0 

1623K 21FLSWFDFLO 37 72 0 10/1/2002 1200 0.50 32209 133.0 

1623K 21FLPOLKP.C. CANAL9 10/23/2002 930 0.30 32223 76.1 

1623K 21FLSWFDFLO 37 72 0 11/4/2002 1040 0.50 32209 241.0 

1623K 21FLSWFDFLO 37 72 0 12/4/2002 1050 0.50 32209 90.6 

1623K 21FLTPA 27552158149358 2/5/2003 1345 0.20 32209 100.0 

1623K 21FLTPA 27552158149358 4/22/2003 1000 0.20 32209 240.0 

1623K 21FLTPA 27552158149358 8/19/2003 950 0.20 32209 260.0 

1623K 21FLTPA 27552158149358 11/4/2003 1145 0.20 32209 54.0 

1623K 21FLPOLKP.C. CANAL9 4/15/2004 955 0.25 32210 148.0 

Lower Saddle Creek Dissolved Oxygen Data 

WBID Station Date Time Depth

Storet 

Code 

DO 

(mg/L) R-Code 

1623K 21FLSWFDFLO0038 3/26/1992 1200 0.80 299 5.12 

1623K 21FLSWFDFLO0038 7/8/1992 1045 2.00 299 1.43 

1623K 21FLSWFDFLO0038 9/22/1992 1420 4.59 299 1.67 

1623K 112WRD 02294491 9/25/1992 1130 0.50 300 7.60 

1623K 112WRD 02294491 10/29/1992 1645 0.50 300 1.40 

1623K 21FLSWFDFLO0038 12/7/1992 1500 1.64 299 12.29 

1623K 21FLPOLKP.C. CANAL9 2/11/1993 1250 0.50 299 6.70 

1623K 112WRD 02294491 4/16/1993 1150 0.50 300 8.00 

1623K 21FLPOLKP.C. CANAL9 5/13/1993 910 0.20 299 5.00 

1623K 112WRD 02294491 7/9/1993 1300 0.50 300 4.00 

1623K 21FLPOLKP.C. CANAL9 8/17/1993 1320 0.30 299 2.60 

1623K 112WRD 02294491 9/23/1993 1130 0.50 300 5.70 

1623K 112WRD 02294491 10/13/1993 1300 0.50 300 7.20 

1623K 21FLPOLKP.C. CANAL9 11/23/1993 910 0.40 299 1.70 

1623K 112WRD 02294491 8/9/1994 1610 0.50 300 13.50 

1623K 112WRD 02294491 8/23/1994 1020 0.50 300 7.90 

1623K 21FLPOLKP.C. CANAL9 8/16/1995 1153 0.60 299 5.40 

1623K 21FLPOLKP.C. CANAL9 11/21/1995 915 0.33 299 6.80 

1623K 21FLPOLKP.C. CANAL9 2/7/1996 928 0.33 299 12.50 

1623K 21FLPOLKP.C. CANAL9 5/21/1996 815 0.33 299 4.10 

1623K 21FLPOLKP.C. CANAL9 8/14/1996 835 0.33 299 5.10 

1623K 21FLPOLKP.C. CANAL9 11/20/1996 825 0.33 299 8.80 

1623K 21FLPOLKP.C. CANAL9 2/12/1997 825 0.00 299 10.34 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 103

WBID Station Date Time Depth

Storet 

Code 

DO 

(mg/L) R-Code 

1623K 21FLPOLKP.C. CANAL9 5/20/1997 830 0.00 299 6.04 

1623K 21FLSWFDFLO 37 72 0 8/4/1997 1200 1.00 299 6.39 

1623K 21FLPOLKP.C. CANAL9 8/12/1997 925 0.80 299 6.88 

1623K 21FLSWFDFLO 37 72 0 9/10/1997 1030 1.00 299 6.44 

1623K 21FLSWFDFLO 37 72 0 10/6/1997 1130 1.00 299 4.71 

1623K 21FLSWFDFLO 37 72 0 11/3/1997 1040 0.30 299 6.68 

1623K 21FLPOLKP.C. CANAL9 11/5/1997 1112 0.70 299 11.03 

1623K 21FLSWFDFLO 37 72 0 12/1/1997 1035 1.40 299 7.18 

1623K 21FLSWFDFLO 37 72 0 1/22/1998 1330 S 299 7.98 

1623K 21FLSWFDFLO 37 72 0 2/2/1998 1040 0.70 299 8.94 

1623K 21FLPOLKP.C. CANAL9 2/10/1998 1130 1.40 299 12.18 

1623K 21FLSWFDFLO 37 72 0 3/2/1998 1015 0.30 299 7.83 

1623K 21FLSWFDFLO 37 72 0 3/26/1998 1030 B 299 7.57 

1623K 21FLSWFDFLO 37 72 0 4/6/1998 1010 0.30 299 6.89 

1623K 21FLSWFDFLO 37 72 0 4/15/1998 1125 B 299 6.70 

1623K 21FLSWFDFLO 37 72 0 5/4/1998 1215 0.30 299 6.13 

1623K 21FLPOLKP.C. CANAL9 5/13/1998 1040 0.80 299 4.76 

1623K 21FLSWFDFLO 37 72 0 5/15/1998 1100 S 299 5.32 

1623K 21FLSWFDFLO 37 72 0 6/1/1998 1045 0.30 299 6.60 

1623K 21FLSWFDFLO 37 72 0 6/16/1998 1345 S 299 9.35 

1623K 21FLSWFDFLO 37 72 0 7/6/1998 1100 0.30 299 1.70 

1623K 21FLSWFDFLO 37 72 0 7/28/1998 1230 S 299 2.95 

1623K 21FLSWFDFLO 37 72 0 8/3/1998 1130 0.60 299 4.00 

1623K 21FLPOLKP.C. CANAL9 8/10/1998 1100 0.70 299 5.91 

1623K 21FLSWFDFLO 37 72 0 8/11/1998 1230 S 299 9.36 

1623K 21FLSWFDFLO 37 72 0 9/8/1998 1015 0.30 299 2.19 

1623K 21FLSWFDFLO 37 72 0 9/10/1998 1245 S 299 7.17 

1623K 21FLSWFDFLO 37 72 0 10/7/1998 900 0.30 299 5.77 

1623K 21FLSWFDFLO 37 72 0 10/12/1998 1545 B 299 5.22 

1623K 21FLSWFDFLO 37 72 0 11/9/1998 1320 S 299 3.54 

1623K 21FLPOLKP.C. CANAL9 11/12/1998 1050 0.50 299 7.20 

1623K 21FLSWFDFLO 37 72 0 12/9/1998 1355 S 299 7.44 

1623K 21FLSWFDFLO 37 72 0 12/17/1998 1130 0.30 299 7.89 

1623K 21FLSWFDFLO 37 72 0 1/5/1999 1615 0.30 299 7.74 

1623K 21FLSWFDFLO 37 72 0 1/7/1999 1355 S 299 7.61 

1623K 21FLPOLKP.C. CANAL9 2/1/1999 1030 0.25 299 8.36 

1623K 21FLSWFDFLO 37 72 0 2/9/1999 1200 0.80 299 7.75 

1623K 21FLSWFDFLO 37 72 0 3/1/1999 1650 0.50 299 8.31 

1623K 21FLSWFDFLO 37 72 0 3/24/1999 1135 S 299 9.06 

1623K 21FLSWFDFLO 37 72 0 4/5/1999 1030 0.80 299 5.05 

1623K 21FLSWFDFLO 37 72 0 4/6/1999 1245 S 299 3.14 

1623K 21FLPOLKP.C. CANAL9 4/14/1999 851 0.50 299 6.07 

1623K 21FLSWFDFLO 37 72 0 5/10/1999 1445 0.65 299 4.61 

1623K 21FLSWFDFLO 37 72 0 6/9/1999 1000 0.75 299 4.89 

1623K 21FLPOLKP.C. CANAL9 7/14/1999 940 0.50 299 5.49 

1623K 21FLSWFDFLO 37 72 0 7/17/1999 925 0.30 299 4.42 

1623K 21FLSWFDFLO 37 72 0 8/16/1999 1030 0.50 299 2.92 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 104

WBID Station Date Time Depth

Storet 

Code 

DO 

(mg/L) R-Code 

1623K 21FLSWFDFLO 37 72 0 9/16/1999 1040 0.50 299 3.15 

1623K 21FLSWFDFLO 37 72 0 10/4/1999 1410 0.50 299 7.97 

1623K 21FLSWFDFLO 37 72 0 11/1/1999 930 0.50 299 7.61 

1623K 21FLSWFDFLO 37 72 0 12/8/1999 1000 0.50 299 7.00 

1623K 21FLSWFDFLO 37 72 0 1/5/2000 1030 0.50 299 9.73 

1623K 21FLPOLKP.C. CANAL9 1/13/2000 950 0.50 299 8.72 

1623K 21FLSWFDFLO 37 72 0 2/8/2000 1130 0.50 299 11.61 

1623K 21FLSWFDFLO 37 72 0 3/15/2000 1100 0.50 299 6.81 

1623K 21FLPOLKP.C. CANAL9 4/17/2000 900 0.50 299 5.35 

1623K 21FLSWFDFLO 37 72 0 5/3/2000 1100 0.50 299 8.42 

1623K 21FLSWFDFLO 37 72 0 5/11/2000 1000 0.50 299 4.51 

1623K 21FLSWFDFLO 37 72 0 6/6/2000 1155 S 299 12.49 

1623K 21FLSWFDFLO 37 72 0 6/8/2000 1100 0.50 299 2.44 

1623K 21FLSWFDFLO 37 72 0 7/6/2000 1340 S 299 9.45 

1623K 21FLPOLKP.C. CANAL9 7/18/2000 710 0.30 299 1.21 

1623K 21FLSWFDFLO 37 72 0 8/1/2000 1145 S 299 10.91 

1623K 21FLSWFDFLO 37 72 0 8/8/2000 1500 0.50 299 1.75 

1623K 21FLSWFDFLO 37 72 0 9/12/2000 1000 0.50 299 4.44 

1623K 21FLSWFDFLO 37 72 0 9/13/2000 1145 S 299 8.83 

1623K 21FLSWFDFLO 37 72 0 10/3/2000 1510 0.50 299 5.97 

1623K 21FLPOLKP.C. CANAL9 10/5/2000 1000 0.50 299 0.47 

1623K 21FLSWFDFLO 37 72 0 10/17/2000 1530 S 299 9.34 

1623K 21FLSWFDFLO 37 72 0 11/1/2000 1120 S 299 9.17 

1623K 21FLSWFDFLO 37 72 0 11/6/2000 1430 0.50 299 5.49 

1623K 21FLSWFDFLO 37 72 0 12/6/2000 1330 0.50 299 3.18 

1623K 21FLPOLKP.C. CANAL9 1/9/2001 1245 0.20 299 9.99 

1623K 21FLSWFDFLO 37 72 0 2/7/2001 1545 0.55 299 15.56 

1623K 21FLPOLKP.C. CANAL9 3/6/2001 1100 0.30 299 5.70 

1623K 21FLSWFDFLO 37 72 0 3/7/2001 945 0.50 299 4.27 

1623K 21FLSWFDFLO 37 72 0 4/3/2001 1015 0.50 299 1.45 

1623K 21FLSWFDFLO 37 72 0 5/9/2001 1040 0.50 299 2.12 

1623K 21FLSWFDFLO 37 72 0 6/5/2001 940 0.32 299 0.31 

1623K 21FLSWFDFLO 37 72 0 8/9/2001 1330 0.50 299 3.97 

1623K 21FLSWFDFLO 37 72 0 9/4/2001 1050 0.50 299 4.87 

1623K 21FLSWFDFLO 37 72 0 10/2/2001 1050 0.50 299 9.60 

1623K 21FLPOLKP.C. CANAL9 10/29/2001 1330 0.50 299 9.01 

1623K 21FLSWFDFLO 37 72 0 1/8/2002 1035 0.50 299 1.45 

1623K 21FLPOLKP.C. CANAL9 1/15/2002 1145 0.33 299 6.55 

1623K 21FLSWFDFLO 37 72 0 2/6/2002 915 0.50 299 0.49 

1623K 21FLSWFDFLO 37 72 0 3/4/2002 1110 0.50 299 3.87 

1623K 21FLSWFDFLO 37 72 0 4/2/2002 1115 0.50 299 0.88 

1623K 21FLPOLKP.C. CANAL9 4/17/2002 1055 0.15 299 4.30 

1623K 21FLSWFDFLO 37 72 0 5/6/2002 1050 0.50 299 0.72 

1623K 21FLSWFDFLO 37 72 0 7/4/2002 1530 0.50 299 7.30 

1623K 21FLPOLKP.C. CANAL9 7/24/2002 930 0.50 299 2.78 

1623K 21FLSWFDFLO 37 72 0 9/5/2002 1700 0.50 299 7.60 

1623K 21FLSWFDFLO 37 72 0 10/1/2002 1200 0.50 299 6.45 
DRAFT DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek, November, 2005 

 105

WBID Station Date Time Depth

Storet 

Code 

DO 

(mg/L) R-Code 

1623K 21FLPOLKP.C. CANAL9 10/23/2002 930 0.30 299 2.42 

1623K 21FLSWFDFLO 37 72 0 11/4/2002 1040 0.50 299 0.52 

1623K 21FLSWFDFLO 37 72 0 12/4/2002 1050 0.50 299 11.16 

1623K 21FLPOLKP.C. CANAL9 1/28/2003 1005 0.50 299 9.52 

1623K 21FLTPA 27552158149358 2/5/2003 1345 0.20 299 7.65 

1623K 21FLPOLKP.C. CANAL9 4/16/2003 930 0.50 299 2.22 

1623K 21FLTPA 27552158149358 4/22/2003 1000 0.20 299 2.31 

1623K 21FLPOLKP.C. CANAL9 7/23/2003 915 0.50 299 0.84 

1623K 21FLTPA 27552158149358 8/19/2003 950 0.20 299 2.82 

1623K 21FLPOLKP.C. CANAL9 10/8/2003 1020 0.50 299 5.54 

1623K 21FLTPA 27552158149358 11/4/2003 1145 0.20 299 8.85 

1623K 21FLPOLKP.C. CANAL9 1/7/2004 940 0.40 299 7.69 

1623K 21FLPOLKP.C. CANAL9 4/15/2004 955 0.25 299 7.38 
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix C 

APPENDIX C: TSI for PC, Background, TMDL Target, and TSI-Unit 

 Percent Reduction 

Banana Lake

TSI for Measured, PC, Background, TMDL Target, TMDL, and 

TSI-unit Percent Reduction Based on Background L50-IL75

Year 

Color 

(PCU) Measured Calibrated

Background 

IL75 

Target 

IL75+5 TMDL

Percent 

Reduction

1994 34.23 83 83 73.9 78.9 78.9 34

1995 48.93 74.1 74.2 57.5 62.5 62.3 60.5

1996 39.64 79.9 80 57.4 62.4 62.3 80.3

1997 35.71 81.9 81.9 48.4 53.4 53.5 89.1

1998 52.62 82 82 51.2 56.2 56.2 87.7

1999 33.5 82.4 82.4 53.3 58.3 58.3 88.5

2000 90.8 90.8 66.2 71.2 71.2 88.7

2001 91.8 91.8 66.1 71.1 71.1 89.9

2002 42 87.2 87.2 56.3 61.3 61.2 90.4

2003 50 77.4 77.3 47.8 52.8 52.9 86.8

Minimum 33.5 74.1 74.2 47.8 52.8 52.9 34

Maximum 52.6 91.8 91.8 73.9 78.9 78.9 90.4

Mean 42.1 83.1 83.1 57.8 62.8 62.8 79.6

Lake Bentley

TSI for Measured, PC, Background, TMDL Target, TMDL, and 

TN and TP Mass Percent Reduction 

Year Measured Calibrated

Background 

IL75 

Target 

IL75+5 TMDL

TN Mass 

Percent 

Reduction 

TP Mass 

Percent 

Reduction 

1994* 71.7 49.3 54.3 54.5 84 69

1995* 70.8 48.9 53.9 54 83 81

1996 79.2 79.2 65.6 70.6 70.6 68 68

1997 74.2 75.2 41.2 46.2 46.8 93 93

1998 75.3 75.2 42.5 47.5 47.6 92.3 92.3

1999 74.8 74.8 42.9 47.9 47.8 90 90

2000 72.2 76.8 51.8 56.8 56.6 84.9 84.4

2001 71.7 75.5 45.7 50.7 50.8 90.7 90.7

2002* 72.6 73.6 43.5 48.5 47.5 95 94

2003 67.3 71.3 40.5 45.5 46.2 89 89

Minimum 67.3 70.8 40.5 45.5 46.2 68 68

Maximum 79.2 79.2 65.6 70.6 70.6 95 94

Mean 73.4 74.4 47.2 52.2 52.2 87 85.1

* Reductions in TP limited by background concentrations. 

1
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix C 

Lake Bonny

TSI for Measured, PC, Background, TMDL Target, TMDL, and 

TSI-unit Percent Reduction Based on Background L50-IL75

Year Measured PC

Background 

IL75 

Target 

IL75+5 TMDL 

Percent 

Reduction 

1994 66.4 66.2 53.3 58.3 58.3 54.5

1995 69.0 68.9 54.7 59.7 59.5 54.5

1996 69.9 70.0 62.4 67.4 67.6 25.0

1997 73.7 73.7 53.4 58.4 58.2 77.0

1998 72.3 72.2 56.4 61.4 61.3 69.0

1999 76.0 76.0 62.2 67.2 67.0 66.0

2000* 86.3 86.3 82.1 84.2 84.1 28.0

2001 87.8 87.8 74.8 79.8 79.7 68.0

2002 74.2 74.2 58.3 63.3 63.1 72.0

2003 67.0 66.9 52.2 57.2 57.1 63.0

Minimum 66.4 66.2 52.2 57.2 57.1 25.0

Maximum 87.8 87.8 82.1 87.1 84.1 77.0

Average 74.3 74.2 61.0 66.0 65.6 57.7

* Target for year 2000 was set at half the difference between IL75 and PC due to a dry year 

 in the background condition. 

Lake Crago 

TSI for Measured, PC, Background, TMDL Target, TMDL, and 

TSI-unit Percent Reduction Based on Background L50-IL75

Year Measured PC

Background 

IL75 

Target 

IL75+5 TMDL

Percent 

Reduction 

1994 59.2 51.9 56.9 56.5 10

1995 59.6 44.5 49.5 49.1 20

1996 73.3 73.3 57.4 62.4 62.1 80

1997 71.6 71.5 47.8 52.8 52.7 85

1998 66.3 66.3 44.9 49.9 49.7 80

1999 73.5 73.5 51.7 56.7 56.8 85

2000 74.3 74.3 57.1 62.1 62.9 90

2001 64.4 64.3 51.4 56.4 56.5 58

2002 72.8 72.8 47 52 52.1 91.5

2003 71.9 70.9 51.9 56.9 57 65

Minimum 64.4 59.2 44.5 49.5 49.1 10

Maximum 74.3 74.3 57.4 62.4 62.9 91.5

Average 71 68.6 50.6 55.6 55.5 66.5

2
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix C 

Eagle Lake 

TSI for Measured, PC, Background, TMDL Target, TMDL, and TSI-unit Percent 

Reduction Based on Background L50-IL75 

Year 

Existing 

Measured Calibrated

Background 

IL75 

Target 

IL75+5 TMDL

Percent 

Reduction 

1994 55.3 58.6 45.46 50.46 47.87 70

1995 53.1 57.2 46.5 51.5 46.49 70

1996 55 60.7 59.88 64.88 51.05 70

1997 50.9 56.7 41.42 46.42 45.48 70

1998 56.8 59.3 48.95 53.95 48.81 70

1999 46.8 61.9 52.57 57.57 53.62 70

2000 50.3 66.9 56.64 61.64 59.37 70

2001 50.8 64 56.71 61.71 55.22 70

2002 49.6 56.3 41.74 46.74 44.83 70

2003 57.4 49.46 54.46 46.63 70

Minimum 46.8 56.34 41.42 46.42 44.83 70

Maximum 56.8 66.91 59.88 64.88 59.37 70

Mean 52.1 59.91 49.93 54.93 49.94 70

Lake Gibson

TSI for Measured, PC, Background, TMDL Target, TMDL, and 

TSI-unit Percent Reduction Based on Background L50-IL75

Year Measured PC

Background 

IL75 

Target 

IL75+5 TMDL

Percent 

Reduction 

1994 43.6 56.4 47.6 52.6 52.5 28

1995 63.2 64.1 44.9 49.9 49.3 68

1996 66.4 68.5 63 68 67.4 9

1997 44.8 57.8 34.4 39.4 39.1 74

1998 53.4 57.2 35.6 40.6 39.9 72

1999 55.8 59 41.4 46.4 46.6 65

2000* 44.9 60.6 61.7 66.7 60.6 

2001 56.5 63.6 51.1 56.1 55.4 55

2002 56.3 60.5 43 48 47.7 60

2003 53 60.8 39 44 42.8 77

Minimum 43.6 56.4 34.4 39.4 39.1 9

Maximum 66.4 68.5 63 68 67.4 77

Average 53.8 60.8 46.2 51.2 50.1 56.4

* Year 2000 not included as the lake in the background condition had higher concentrations

 than the current condition. 

3
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix C 

Lake Hollingsworth 

TSI for Measured, PC, Background, TMDL Target, TMDL, and 

TN and TP Mass Percent Reduction 

Year Measured Calibrated

Background 

IL75 

Target 

IL75+5 TMDL

TN Mass 

Percent 

Reduction 

TP Mass 

Percent 

Reduction 

1994* 88.4 88.3 57.7 62.7 62.8 92.2 88

1995* 90.8 90.9 61.4 66.4 66.3 93 83

1996 89.6 89.6 78.8 83.8 83.8 50 50

1997* 89.1 89.1 52.9 57.9 57.8 93.2 89

1998* 82.7 82.7 52 57 56.4 90 85

1999* 84.5 84.6 54.2 59.2 58.9 90 87

2000** 86.4 88.6 81.7 84.1 83.9 40.5 37

2001 87.1 87 58.8 63.8 63.8 88 88

2002* 72.6 72.6 47.9 52.9 52.8 82.5 75

2003* 70.3 73.3 44.5 49.5 49.1 84 82

Minimum 70.3 72.6 44.5 49.5 49.1 40.5 37

Maximum 90.8 90.9 81.7 84.1 83.9 93.2 89

Mean 84.2 84.7 59 63.7 63.6 80.3 76.4

* Reductions in TP limited by background concentrations. 

** Used 1/2 of the difference between PC and Background as target for TMDL due to background concentrations greater 

 than existing. 

Lake Lena 

TSI for PC, Background, TMDL Target, TMDL, and 

TSI-unit reduction Based on Background L50-IL75 

Year PC

Background 

IL75 

Target 

IL75+5 TMDL

Percent 

Reduction 

1994 72.5 60.28 65.28 65.06 51

1995 66.31 57.84 62.84 62.14 35

1996 66.69 57.76 62.76 62.43 35

1997 64.84 55.81 60.81 60.25 37

1998 64.07 56.07 61.07 61.06 26

1999 69.3 58.14 63.14 63.13 52

2000 76.24 67.11 72.11 72.1 42

2001 74.49 64.27 69.27 69.29 45

2002 73.75 63.85 68.85 68.61 38

2003 71.99 58.93 63.93 63.91 49.5

Minimum 64.07 55.81 60.81 60.25 26

Maximum 76.24 67.11 72.11 72.1 52

Average 70.02 60.01 65.01 64.8 41.1

4
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix C 

Lake Parker

TSI for Measured, PC, Background, TMDL Target, TMDL, and 

TSI-unit Percent Reduction Based on Background L50-IL75

Year 

PCU 

Color Measured PC

Background 

IL75 

Target 

IL75+5 TMDL

Percent 

Reduction 

1994 23.5 78.8 78.7 65.1 70.1 69.9 61

1995 25 74.9 75 57.1 62.1 62 67.5

1996 27.4 78.7 78.7 70.5 75.5 75.5 28

1997 48.6 83.1 83.1 61.3 66.3 66.2 78.5

1998 82 81.5 81.5 61.2 66.2 66 76.8

1999 32 86 86 74.3 79.3 79.4 54.6

2000* 32 90.7 90.7 89.8 89.8 89.8 10

2001 55.3 87.8 87.8 76.2 81.2 81.1 58

2002 34 84.3 84.3 67.1 72.1 71.9 75.1

2003 53.8 77.4 77.4 61.3 66.3 66.3 66.2

Minimum 23.5 74.9 75 57.1 62.1 62 10

Maximum 82 90.7 90.7 89.8 89.9 89.8 78.5

Average 38.2 82.3 82.3 68.4 72.9 72.8 57.6

* Used natural land use (IL75) as TMDL target because background plus 5 TSI units was greater 

than the existing condition (measured condition). 

Spirit Lake 

TSI for Measured, PC, Background, TMDL Target, TMDL, and TSI-unit Percent 

Reduction Based on Background L50-IL75 

Year 

Existing 

Measured Calibrated

Background 

IL75 

Target 

IL75+5 TMDL

Percent 

Reduction 

1994 75.9 70.42 75.42 70.18 55

1995 71 69.16 74.16 64.76 55

1996 76.4 70.13 75.13 71.21 55

1997 51.3 61.1 50.36 55.36 54.2 55

1998 56.6 66.5 59.62 64.62 60.04 55

1999 48.5 67.3 60.71 65.71 62.06 55

2000 53.7 70.1 64.15 69.15 64.7 55

2001 51.8 69.9 62.7 67.7 64.56 55

2002 51.3 64.4 53.7 58.7 57.21 55

2003 51.2 63.7 62.22 67.22 57.26 55

Minimum 48.5 61.11 50.36 55.36 54.2 55

Maximum 56.6 76.38 70.42 75.42 71.21 55

Mean 52.1 68.63 62.32 67.32 62.62 55

5
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix D 

1

Appendix D: Lake Hancock Basin Modeled Lakes Mass for TN and TP for 

 Calibrated Model, TMDL, and Percent Reduction 

Banana Lake 

Mass for TN and TP for Calibrated Model and TMDL, 

with Mass Percent Reductions (kg/year) 

Year 

TN-MASS 

Calibrated 

TN-MASS 

TMDL 

TN-MASS 

% Reduction

TP-MASS 

Calibrated 

TP-MASS 

TMDL 

TP-MASS 

% Reduction

1994 78,712.1 50,039.7 36.4 141,282.7 93,190.9 34.0 

1995 45,448.0 17,227.0 62.1 135,638.2 53,593.0 60.5 

1996 42,615.2 9,373.2 78.0 97,385.7 19,276.7 80.2 

1997 94,168.5 11,160.9 88.1 111,217.9 12,286.5 89.0 

1998 81,718.7 10,616.6 87.0 125,292.0 15,516.4 87.6 

1999 53,454.0 6,283.2 88.2 75,148.4 8,672.1 88.5 

2000 88,872.9 10,175.7 88.6 104,952.1 11,886.2 88.7 

2001 152,977.7 15,734.1 89.7 139,287.0 14,120.9 89.9 

2002 147,416.3 15,170.1 89.7 139,618.9 13,504.6 90.3 

2003 83,547.1 11,665.8 86.0 106,314.2 14,231.5 86.6 

Minimum 42,615.2 6,283.2 36.4 75,148.4 8,672.1 34.0 

Maximum 152,977.7 50,039.7 89.7 141,282.7 93,190.9 90.3 

Mean 86,893.0 15,744.6 79.4 117,613.7 25,627.9 79.5 

Lake Bentley 

Mass for TN and TP for Calibrated Model and TMDL, 

with Mass Percent Reductions (kg/year) 

Year 

TN-MASS 

Calibrated 

TNMASS 

TMDL 

TN-MASS 

% 

Reduction 

TP-MASS 

Calibrated

TPMASS 

TMDL 

TP-MASS 

% 

Reduction 

1994* 11718.3 2110.6 82 777.6 231.5 70.2 

1995* 14857.2 2598.2 82.5 658 204.8 68.9 

1996 8935.3 3549.6 60.3 1678.7 582.3 65.3 

1997 19613 2426 87.6 3979.1 492.8 87.6 

1998 13588.2 1720.5 87.3 4592 449.1 90.2 

1999 4153.5 478.6 88.5 1728.4 182.7 89.4 

2000 3372.5 526.1 84.4 1443.4 225.2 84.4 

2001 5950.3 784.1 86.8 2480.2 270.7 89.1 

2002* 10424.6 1940.8 81.4 3293.5 298.5 90.9 

2003 9710.4 1662.8 82.9 8596.9 1027.5 88 

Minimum 3372.5 478.6 60.3 658 182.7 65.3 

Maximum 19613 3549.6 88.5 8596.9 1027.5 90.9 

Mean 10232.3 1779.7 82.4 2922.8 396.5 82.4 

* Reductions in TP limited by background concentrations. 
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix D 

2

Lake Bonny 

Mass for TN and TP for Calibrated Model and TMDL, 

with Mass Percent Reductions (kg/year) 

Year 

TN-MASS 

Calibrated 

TN-MASS 

TMDL 

TN-MASS 

% Reduction

TP-MASS 

Calibrated 

TP-MASS 

TMDL 

TP-MASS 

% Reduction 

1994 10,059.0 4,576.8 54.5 719.2 327.2 54.5 

1995 9,062.8 4,123.6 54.5 1,605.6 730.5 54.5 

1996 10,031.4 7,523.5 25.0 1,241.1 930.8 25.0 

1997 20,827.0 4,790.2 77.0 6,615.3 1,521.5 77.0 

1998 15,320.9 4,749.5 69.0 1,706.9 529.1 69.0 

1999 11,479.9 3,903.2 66.0 1,568.9 533.4 66.0 

2000* 17,405.3 12,531.7 28.0 2,030.3 1,461.8 28.0 

2001 29,067.4 9,301.6 68.0 4,604.5 1,473.4 68.0 

2002 35,883.1 10,047.3 72.0 2,597.4 727.3 72.0 

2003 11,699.1 4,328.5 63.0 1,287.9 476.5 63.0 

Minimum 9,062.8 3,903.2 25.0 719.2 327.2 25.0 

Maximum 35,883.1 12,531.7 77.0 6,615.3 1,521.5 77.0 

Average 17,083.6 6,587.6 57.7 2,397.7 871.2 57.7 

* Target for year 2000 was set at half the difference between IL75 and PC due to a dry year 

 in the background condition. 

Lake Crago 

Mass for TN and TP for Calibrated Model and TMDL, 

with Mass Percent Reductions (kg/year) 

Year 

TN-MASS 

Calibrated 

TNMASS 

TMDL 

TN-MASS 

% 

Reduction 

TP-MASS 

Calibrated

TPMASS 

TMDL 

TP-MASS 

% 

Reduction 

1994 6,181.7 5,114.2 17.3 1,191.9 1,015.4 14.8 

1995 6,354.0 3,162.7 50.2 1,033.6 601.8 41.8 

1996 16,026.3 5,648.0 64.8 5,224.1 1,342.3 74.3 

1997 17,612.7 4,329.9 75.4 11,090.6 2,146.9 80.6 

1998 8,963.0 2,879.1 67.9 4,267.7 1,074.6 74.8 

1999 12,199.9 2,846.4 76.7 3,875.0 749.3 80.7 

2000 8,841.5 2,741.4 69.0 2,955.7 484.7 83.6 

2001 4,945.7 2,698.4 45.4 4,521.1 1,952.9 56.8 

2002 19,639.6 4,233.6 78.4 4,385.2 693.6 84.2 

2003 9,748.1 3,460.9 64.5 2,444.3 887.3 63.7 

Minimum 4,945.7 2,698.4 17.3 1,033.6 484.7 14.8 

Maximum 19,639.6 5,648.0 78.4 11,090.6 2,146.9 84.2 

Average 11,051.3 3,711.5 61.0 4,098.9 1,094.9 65.5 
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix D 

3

Eagle Lake 

Mass for TN and TP for Calibrated Model and TMDL, 

with Mass Percent Reductions (kg/year) 

Year 

TN-MASS 

Calibrated 

TNMASS 

TMDL 

TN-MASS 

% 

Reduction 

TP-MASS 

Calibrated

TPMASS 

TMDL 

TP-MASS 

% 

Reduction 

1994 21,801.6 6,540.5 70 624.6 187.4 70 

1995 22,129.8 6,639.0 70 647.2 194.2 70 

1996 15,462.0 4,638.6 70 560.3 168.1 70 

1997 28,597.2 8,579.2 70 811.8 243.5 70 

1998 19,421.4 5,826.4 70 851.8 255.6 70 

1999 15,395.9 4,618.8 70 510.2 153.1 70 

2000 17,420.4 5,226.1 70 489.6 146.9 70 

2001 21,855.3 6,556.6 70 543.6 163.1 70 

2002 25,974.2 7,792.3 70 753.4 226 70 

2003 19,534.5 5,860.3 70 613.5 184.1 70 

Minimum 15,395.9 4,618.8 70 489.6 146.9 70 

Maximum 28,597.2 8,579.2 70 851.8 255.6 70 

Mean 20,759.2 6,227.8 70 640.6 192.2 70 

Lake Gibson 

Mass for TN and TP for Calibrated Model and TMDL, 

with Mass Percent Reductions (kg/year) 

Year 

TN-MASS 

Calibrated 

TNMASS 

TMDL 

TN-MASS 

% 

Reduction 

TP-MASS 

Calibrated

TPMASS 

TMDL 

TP-MASS 

% 

Reduction 

1994 10,815.4 7,787.1 28 5,622.7 4,048.3 28 

1995 13,422.2 4,295.1 68 4,428.9 1,417.3 68 

1996 8,323.0 7,573.9 9 1,948.3 1,772.9 9 

1997 16,079.5 4,180.7 74 10,354.5 2,692.2 74 

1998 12,176.4 3,409.4 72 4,401.6 1,232.5 72 

1999 8,676.8 3,036.9 65 2,882.7 1,008.9 65 

2000* 8,950.2 8,950.2 1,652.0 1,652.0 

2001 10,787.6 4,854.4 55 1,197.1 538.7 55 

2002 12,066.5 4,829.2 60 2,414.0 965.6 60 

2003 13,944.7 3,207.3 77 2,248.5 517.5 77 

Minimum 8,323.0 3,036.9 9 1,197.1 517.5 9 

Maximum 16,079.5 8,950.2 77 10,354.5 4,048.3 77 

Average 11,524.2 5,212.4 56.4 3,715.0 1,584.6 56.4 

*Year 2000 not included as the lake in the background condition had higher concentrations than the 

current condition. 
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix D 

4

Lake Hollingsworth 

Mass for TN and TP for Calibrated Model and TMDL, 

with Mass Percent Reductions (kg/year) 

Year 

TN-MASS 

Calibrated 

TN-MASS 

TMDL 

TN-MASS 

% Reduction 

TP-MASS 

Calibrated 

TP-MASS 

TMDL 

TP-MASS 

% Reduction 

1994* 52,471.0 4,092.7 92.2 7,376.5 885.2 88 

1995* 59,081.4 4,135.7 93.0 4,380.1 744.6 83 

1996 31,496.1 15,748.1 50.0 2,581.2 1,290.6 50 

1997* 49,304.1 3,352.5 93.2 6,633.2 729.7 89 

1998* 28,281.7 2,828.2 90.0 3,286.4 493.2 85 

1999* 16,565.5 1,656.6 90.0 2,505.4 325.6 87 

2000** 9,500.9 5,653.1 40.5 1,927.6 1,214.2 37 

2001 16,898.6 2,196.6 87.0 3,611.2 587.4 83.7 

2002* 19,806.3 3,466.1 82.5 1,113.7 278.4 75 

2003* 15,868.4 2,538.9 84.0 2,477.6 445.8 82 

Minimum 9,500.9 1,656.6 40.5 1,113.7 278.4 37 

Maximum 59,081.4 15,748.1 93.2 7,376.5 1,290.6 89 

Mean 29,927.4 4,566.8 80.2 3,589.3 699.5 76 

* Reductions in TP limited by background concentrations. 

** Used 1/2 of the difference between PC and Background as target for TMDL due to background concentrations 

 greater than existing. 

Lake Lena 

Mass for TN and TP for Calibrated Model and TMDL, 

with mass percent reductions (kg/year) 

Year 

TN-MASS 

Calibrated 

TNMASS 

TMDL 

TN-MASS 

% 

Reduction 

TP-MASS 

Calibrated

TPMASS 

TMDL 

TP-MASS 

% 

Reduction 

1994 15225.1 7460.3 51 566.1 277.4 51 

1995 19333.9 12567 35 776.6 504.8 35 

1996 4681.8 3043.2 35 229.3 149 35 

1997 15377.8 9688 37 732.4 461.4 37 

1998 18579.7 13749 26 794.6 588 26 

1999 1861 893.3 52 290 139.2 52 

2000 2326.6 1349.4 42 270.7 157 42 

2001 4203.1 2311.7 45 235 129.2 45 

2002 22247.5 13793.5 38 374.8 232.4 38 

2003 29676.6 14986.7 49.5 887.8 448.3 49.5 

Minimum 1861 893.3 26 229.3 129.2 26 

Maximum 29676.6 14986.7 52 887.8 588 52 

Average 13351.3 7984.2 41 515.7 308.7 41 
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix D 

Lake Parker

Mass for TN and TP for Calibrated Model and TMDL, 

with Mass Percent Reductions (kg/year) 

Year 

TN-MASS 

Calibrated 

TNMASS 

TMDL 

TN-MASS 

% 

Reduction 

TP-MASS 

Calibrated

TPMASS 

TMDL 

TP-MASS 

% 

Reduction 

1994 147,935.2 59,825.4 59.6 16,314.2 6,628.2 59.4

1995 103,119.6 34,635.3 66.4 20,010.6 6,680.1 66.6

1996 103,530.0 72,696.3 29.8 12,270.2 8,578.1 30.1

1997 224,461.3 49,839.9 77.8 47,919.0 10,747.1 77.6

1998 161,813.0 38,516.0 76.2 127,686.9 29,837.5 76.6

1999 161,928.1 72,991.8 54.9 16,154.1 7,289.3 54.9

2000* 116,177.3 103,220.2 11.2 52,033.6 46,620.0 10.4

2001 217,593.1 91,996.3 57.7 25,250.8 10,750.2 57.4

2002 416,935.2 104,882.1 74.8 35,839.4 9,031.3 74.8

2003 173,894.3 59,421.4 65.8 5,768.9 2,096.3 63.7

Minimum 103,119.6 34,635.3 11.2 5,768.9 2,096.3 10.4

Maximum 416,935.2 104,882.1 77.8 127,686.9 46,620.0 77.6

Average 182,738.7 68,802.5 57.4 35,924.8 13,825.8 57.1

* Used natural landuse (IL75) as TMDL target becuase background plus 5 TSI units was greater than the existing condition 

(measured condition). 

Spirit Lake 

Mass for TN and TP for Calibrated Model and TMDL, 

with Mass Percent Reductions (kg/year) 

Year 

TN-MASS 

Calibrated 

TNMASS 

TMDL 

TN-MASS 

% 

Reduction 

TP-MASS 

Calibrated

TPMASS 

TMDL 

TP-MASS 

% 

Reduction 

1994 159.7 71.9 55 4,763.4 2,143.5 55

1995 190.6 85.7 55 5,624.3 2,530.9 55

1996 151.5 68.2 55 3,955.4 1,779.9 55

1997 261.3 117.6 55 7,601.4 3,420.6 55

1998 240.6 108.2 55 5,268.1 2,370.6 55

1999 144 64.8 55 3,384.1 1,522.9 55

2000 120.6 54.3 55 3,086.9 1,389.1 55

2001 127.7 57.5 55 4,070.3 1,831.7 55

2002 265.3 119.4 55 7,608.7 3,423.9 55

2003 232 104.4 55 5,790.5 2,605.7 55

Minimum 120.6 54.3 55 3,086.9 1,389.1 55

Maximum 265.3 119.4 55 7,608.7 3,423.9 55

Mean 189.3 85.2 55 5,115.3 2,301.9 55

5
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix E 

1

Appendix E: Lake Hancock Basin Modeled Lakes Annual Average Concentrations for TN, TP

 and Chlorophyll 

a

Banana Lake Annual Average Concentrations for TN, TP, and Chlorophyll 

a (

μg/L

Year 

Measured 

TN 

Calibrated 

TN 

TMDL 

TN 

Background 

TN 

Measured 

TP 

Calibrated 

TP 

TMDL 

TP 

Background 

TP 

Measured 

Chl 

a

1994 2585 2584.8 1928 1443.3 816.6 816.9 657.

6 189.9 122.8 

1995 1702.5 1703.8 841.4 660.6 770.9 770.

6 472.4 158.6 66.3 

1996 2065 2065.2 726.1 570.6 762.4 762.6 324.7 187.2 111.1 1997 2433.8 2433.3 476.6 385.9 643.4 643.1 189.5 115.5 114.6 1998 2411.3 2410.2 534.6 430.9 717.3 717.1 231.3 127.2 118.2 1999 2719.3 2719.7 645.3 512.9 751.4 751.3 238.8 152.5 104.2 2000 4334.5 4333.9 1149.5 870.9 1051.2 1051 337.5 269.8 167.5 2001 4762.5 4761.6 1147 864.5 983 984.2 294.

8 219.5 166.4 

2002 3355.8 3354.9 656.8 519.7 736 736.7 205.2 144 147.5 2003 2438 2438.4 574.8 457.8 657.5 657 219.8 125.2 61 

Minimum 1702.5 1703.8 476.6 385.9 643.4 643.1 189.5 115.5 61 

Maximum 4762.5 4761.6 1928 1443.3 1051.2 1051 657.6 269.8 167.5 

Mean 2880.8 2880.6 868 671.7 789 789.1 317.1 168.9 118 
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix E 

2

Lake Bentley Annual Average Concentrations for TN, TP, and Chlorophyll 

a (

μg/L) 

Year 

Measured 

TN 

Calibrated 

TN 

TMDL 

TN 

Background 

TN 

Measured 

TP 

Calibrated 

TP 

TMDL 

TP 

Background 

TP 

Measured 

Chl 

a

1994* 2136.8 619.5 484 112 50.9 50.8 1995* 2347.7 667.1 443.4 94.

9 43.1 42.8 

1996 2472 2472.5 1383.8 1111 237.3 237 130.

6 84 79.6 

1997 2138 2373.3 467.3 367.6 241 241.5 64.

4 53.9 47.5 

1998 2186.7 2186.8 467.2 375.6 293.3 293.8 73.1 58.6 53.7 1999 2018.8 2018.7 465.9 383.2 308 308.3 87.1 55.8 56.8 2000 1553.8 2387.7 729.5 576.6 369 369.

7 134 119 58.3 

2001 1531.4 2187.6 549.4 437.7 331.9 331 94.8 72.4 55.2 

2002* 1437.3 1577.6 408.5 344.4 221.1 221.

6 46.8 43.3 69.4 

2003 1192.3 1740.8 451.5 357.1 413 413.4 123.4 79.6 43.5 

Minimum 1192.3 1577.6 408.5 344.4 221.1 94.9 43.1 42.8 43.5 Maximum 2472 2472.5 1383.8 1111 413 413.4 134 119 79.6 Mean 1816.3 2143 621 488.1 301.8 262.3 84.8 66 58 

* Reductions in TP limited by background concentrations. 

Lake Bonny Annual Average Concentrations for TN, TP, and Chlorophyll 

a (

μg/L) 

Year 

Measured 

TN 

Calibrated 

TN 

TMDL 

TN 

Measured 

TP 

Calibrated 

TP 

TMDL 

TP 

Measured 

Chl 

a

Calibrated 

Chl 

a

TMDL 

Chl 

a

1994 1,417.8 1,418.0 869.9 82.

5 82.9 51.9 38.7 35.7 23.8

1995 1,238.5 1,238.9 754.7 121.

5 121.4 77.7 47.7 37.8 29.4

1996 1,723.9 1,724.5 1,459.4 137.

3 137.2 117.1 40.0 45.6 35.7

1997 1,834.5 1,834.3 729.4 238.

5 238.1 106.4 56.3 54.7 25.9

1998 1,692.5 1,692.7 831.4 125.

3 125.4 64.5 59.9 43.0 32.3

1999 2,331.3 2,331.4 1,244.8 195.

8 195.3 108.1 60.2 60.0 38.9

2000 4,471.3 4,470.8 3,744.1 341.

4 341.8 287.6 111.8 86.4 104.4

2001 4,053.8 4,053.8 2,145.7 359.

9 360.6 196.7 141.5 86.1 105.3

2002 2,542.5 2,542.0 1,197.6 145.

6 145.4 70.3 53.2 53.6 30.8

2003 1,420.1 1,420.6 767.7 105.

9 105.5 59.5 35.7 37.9 20.1

Note: Background values not provided. 
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix E 

3

Lake Crago Annual Average Concentrations for TN, TP, and Chlorophyll 

a (

μg/L) 

Year 

Measured 

TN 

Calibrated 

TN 

TMDL 

TN 

Measured 

TP CalibratedTP

TMDL 

TP 

Measured 

Chl 

a

Calibrated 

Chl 

a

TMDL 

Chl 

a

1994 847.9 726.9 97.0 87.4 23.5 20.5 1995 880.8 494.7 89.1 62.0 23.6 13.0 1996 2,010.3 2,009.9 960.1 256.

3 257.0 117.3 46.4 46.5 29.5

1997 1,674.7 1,674.9 537.3 344.

0 345.1 130.5 47.9 47.0 19.0

1998 1,168.7 1,168.9 466.3 212.

8 212.6 92.3 39.1 39.2 15.4

1999 1,910.0 1,909.8 679.7 240.

0 239.6 92.7 51.1 51.1 23.6

2000 1,972.5 1,971.5 913.5 250.

7 250.8 90.5 54.7 54.4 30.3

2001 1,092.0 1,092.7 697.7 272.

0 272.8 171.2 33.2 32.8 21.6

2002 1,784.0 1,784.6 514.8 199.

6 199.7 60.0 51.3 51.2 18.5

2003 1,279.3 1,279.7 565.8 155.

6 156.0 83.3 74.5 64.9 31.7

Note: Background values not provided. 

Eagle Lake Annual Average Concentrations for TN, TP, and Chlorophyll 

a (

μg/L) 

Year 

Measured 

TN 

Calibrated 

TN 

TMDL 

TN 

Background 

TN 

Measured 

TP 

Calibrated 

TP 

TMDL 

TP 

Background 

TP 

Measured 

Chl 

a

1994 1,091.5 1,559.2 798.7 465.6 42.3 55.

8 28.1 37.5 15.3 

1995 858.7 1,487.7 761.8 509.5 48.5 53.

8 27.1 41.4 12.2 

1996 838.3 1,860.0 967.2 1,279.3 27.8 76.

7 39.6 97.1 14.7 

1997 749.3 1,379.9 698.8 381.2 28.1 48.3 24 30 14 1998 878.0 1,367.5 698.7 536.5 61.5 61.

7 31.5 43.5 17.3 

1999 517.0 3,180.9 1,688.7 1,100.1 33.8 126.5 66.7 87.4 9.1 2000 640.0 4,188.2 2,294.0 1,296.1 19.5 154.8 84.8 100.8 13.6 2001 688.3 3,261.2 1,724.1 1,267.7 20.

7 111.1 57.9 95.9 13.3 

2002 691.0 1,386.5 696.5 403.7 18.3 49 24.1 31.6 13.7 2003 670.0 1,403.5 717.4 587.8 23.8 52.

8 26.6 45.7 

Minimum 517.0 1,367.5 696.5 381.2 18.

3 48.3 24 30 9.1 

Maximum 1,091.5 4,188.2 2,294.0 1,296.1 61.5 154.8 84.8 100.8 17.3 

Mean 762.2 2,107.5 1,104.6 782.8 32.

4 79 41 61.1 13.7 
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix E 

4

Lake Gibson Annual Average Concentrations for TN, TP, and Chlorophyll 

a (

μg/L) 

Year 

Measured 

TN 

Calibrated 

TN 

TMDL 

TN 

Measured 

TP 

Calibrated 

TP 

TMDL 

TP 

Measured 

Chl 

a

Calibrated 

Chl 

a

TMDL 

Chl 

a

1994 714.3 1,181.9 949.9 221.5 222.1 185.3 3.5 9.8 7.91995 1,196.7 1,302.2 594.2 188.0 187.6 97.7 24.7 24.7 10.21996 997.3 1,209.5 1,137.9 146.5 145.9 138.3 50.7 50.4 47.61997 666.4 1,274.9 489.2 266.3 266.0 125.2 4.6 10.6 3.31998 900.1 1,249.3 513.4 190.8 190.6 91.7 9.6 10.0 3.41999 1,123.9 1,486.0 746.3 213.8 213.6 118.6 9.7 10.0 4.9

2000* 658.6 2,108.9 2,108.9 215.1 214.8 214.8 4.8 7.4 7.4

2001 823.3 1,686.4 1,013.8 130.0 130.0 81.2 17.0 17.4 10.72002 712.5 1,065.4 554.3 118.5 118.7 68.1 20.5 20.0 9.12003 685.0 1,359.4 487.6 130.4 130.3 53.2 13.8 13.7 4.1

*Year 2000 not included as the lake in the background condition had higher concentrations than the current condition. Background values 

Not provided. 

Lake Hollingsworth Annual Average Concentrations for TN, TP, and Chlorophyll 

a (

μg

Year 

Measured 

TN 

Calibrated 

TN 

TMDL 

TN 

Background 

TN 

Measured 

TP 

Calibrated 

TP 

TMDL 

TP 

Background 

TP 

Measured 

Chl 

a

1994* 2585 4682.5 897.6 688.7 816.6 394 116.1 115 122.8 1995* 1702.5 4655.2 831.4 648.8 770.9 274 96.1 89.3 66.3 

1996 2065 4130.6 2745.3 1907.7 762.4 261.7 176.6 133.8 111.1 

1997* 2433.8 3802.5 588.2 468.6 643.4 313.

9 82.9 81.6 114.6 

1998* 2411.3 2965.5 616.3 496.9 717.3 229 72.6 70.9 118.2 1999* 2719.3 3626 786.3 621.2 751.4 329.5 99.2 96.3 104.2 

2000** 4334.5 4183.7 3062 2678.3 1051.2 450.

8 349.7 347.8 167.5 

2001 4762.5 3795 977.5 756.4 983 419.7 147.

5 140.6 166.4 

2002* 3355.8 2171.2 619.8 430.6 736 110.

4 43 42.8 147.5 

2003* 2438 2075 565.8 454.9 657.5 195.3 67.9 66.8 61 

Minimum 1702.5 2075 565.8 430.6 643.4 110.4 43 42.8 61 

Maximum 4762.5 4682.5 3062 2678.3 1051.2 450.

8 349.7 347.8 167.5 

Mean 2880.8 3608.7 1169 915.2 789 297.8 125.2 118.5 118 

* Reductions in TP limited by background concentrations. ** Used 1/2 of the difference between PC and Background as target for TMDL due to background concentrations greater than existing. 
Draft DO and Nutrient TMDL Report for Lake Hancock and Lower Saddle Creek – Appendix E 

5

Lake Parker Annual Average Concentrations for TN, TP, and Chlorophyll 

a (

μg/L) 

Year 

Measured 

TN 

Calibrated 

TN 

TMDL 

TN 

Measured 

TP 

Calibrated 

TP 

TMDL 

TP 

Measured 

Chl 

a

Calibrated 

Chl 

a

TMDL 

Chl 

a

1994 2349.8 2350.3 1318.8 175 175.5 103.3 94 93.4 57.61995 1815 1815.7 872.6 190 190.4 100.3 67.6 67.8 33.51996 2316 2316.7 1865.8 182.3 182 148.4 92.3 92 781997 2586.5 2586.8 952.8 275 275.6 116.6 123.8 123 52.81998 2469 2468.9 976.5 532.3 532.3 244.3 106.4 106 49.51999 3629 3629.5 2269.1 256.5 255.

9 163.8 148.4 148.7 109.1

2000* 4507.5 4507 4216.6 709.9 710.5 671 155.7 155.5 151.5

2001 4428.5 4428.8 2685.6 337.3 337.

3 210.7 139.9 139.9 104.9

2002 3729.1 3729.7 1591.1 233.4 233.

4 104.6 122.9 122.1 66.3

2003 2584.5 2584.4 1314.3 94.4 94.

8 49.4 109.1 108.6 56.3

* Used natural land use (IL75) as TMDL target because background plus 5 TSI units was greater than the existing condition (measured condition). 

Background values not provided. 

Spirit Lake Annual Average Concentrations for TN, TP, and Chlorophyll 

a (

μg/L) 

Year 

Measured 

TN 

Calibrated 

TN 

TMDL 

TN 

Background 

TN 

Measured 

TP 

Calibrated 

TP 

TMDL 

TP 

Background 

TP 

Measured 

Chl 

a

1994 3,823.5 2,498.5 1,783.8 152.6 99.2 137.3 1995 2,705.9 1,753.0 1,662.8 107.8 69.4 129.6 1996 3,898.7 2,615.3 1,824.1 50 168.2 112.8 134.3 1997 580 2,114.6 1,352.6 754.3 33.4 83.

7 53.1 58.4 12.2 

1998 796.6 2,100.6 1,350.7 1,017.5 22.8 97.9 62.9 78.2 26.5 1999 585 3,715.5 2,492.5 1,753.7 29.3 169 113.3 131.8 13.8 2000 780 3,811.5 2,556.8 1,884.3 27.1 166.1 111.4 141.7 19.8 2001 696.3 4,715.5 3,163.2 2,019.7 23.8 184.1 123.5 148.4 17 2002 645 2,391.4 1,518.5 862.0 26.5 95.

2 59.9 68 18.3 

2003 642.5 2,291.5 1,476.7 1,546.0 99.6 63.9 116.6 17 

Minimum 580 2,100.6 1,350.7 754.3 22.

8 83.7 53.1 58.4 12.2 

Maximum 796.6 4,715.5 3,163.2 2,019.7 50 184.1 123.5 148.4 26.5 

Mean 675.1 3,156.8 2,077.8 1,510.8 30.4 132.4 86.9 114.4 17.8 
Appendix F: SWET Watershed Assessment Model (WAM) Final 

Report for the Lake Hancock and Saddle Creek Basin (available 

upon request) 

 

Appendix G: QEA, LLC, BATHTUB Model Final Report for the 

Lake Hancock and Saddle Creek Basin (available upon request) 

Appendix H: WAM Watershed Assessment Model, Model 

Documentation and Users Manual, Soil and Water Engineering 

Technology, Inc., May, 2005 (available upon request)